When I served as counselor of the State Department, I advised the secretary of state about America’s wars with Iraqi insurgents, the Taliban, Iran’s Islamic Revolutionary Guard Corps, and al-Qaeda. I spent a good deal of time visiting battlefields in the Middle East and Afghanistan as well as shaping strategy in Washington. But when I left government service in 2009, I eagerly resumed work on a book that dealt with America’s most durable, and in many ways most effective and important, enemy: Canada.

So I feel both morally compelled and professionally qualified to examine the Trump administration’s interesting but far from original idea of absorbing that country into the union.

There are, as Donald Trump and Don Corleone might put it, two ways of doing this: the easy way and the hard way. The easy way would be if Canadians rose up en masse clamoring to join the United States. Even so, there would be awkwardness.

[Read: The angry Canadian]

Canada is slightly larger than America. That would mean that the “cherished 51st state,” as Trump calls it, would be lopsided in terms of territory. It would be 23 times larger than California, which would be fine for owning the libs, but it would also be 14 times larger than the Lone Star State, which would definitely cause some pursed lips and steely looks there. Messing with Texas is a bad idea.

The new state would be the largest in population too, with 40 million people—more than California by a hair, and considerably more than Texas, Florida, or New York. Its size would pose a whole bunch of problems for Trump: Canada is a much more left-wing country than the United States, and absorbing it could well revive the political fortunes of progressives. If its 10 provinces became 10 states instead of one, only three would probably vote for the GOP; the other seven would likely go for Democrats. That might mean adding six Republican senators and 14 Democrats. If Trump were impeached a third time, that might produce the supermajority required for conviction in the Senate.

But such political ramifications are purely academic considerations at the moment. Polling suggests that 85 to 90 percent of all Canadians cling to sovereignty. Having been denied the easy way of absorbing Canada, therefore, the United States might have to try the hard way, conquering the country and administering it as a territory until it is purged of Liberals, Conservatives, and whatever the Canadian equivalent of RINOs turns out to be.

Unfortunately, we have tried this before, with dismal results. In 1775, before the United States had even formally declared independence from Great Britain, it launched an invasion of Canada, hoping to make it the 14th colony. The psychological-warfare geniuses in Congress ordered that the local farmers and villagers be distributed pamphlets—translated into French—declaring, “You have been conquered into liberty,” an interesting way of putting it. Unfortunately, the Catholic farmers and villagers were largely illiterate, and their leaders, the gentry and parish priests who could read, were solidly on the side of the British against a bunch of invading Protestants.

There were moments of brilliant leadership in this invasion, particularly in a daring autumn march through Maine to the very walls of Quebec. There was also a great deal of poltroonery and bungling. The Americans had three talented generals. The first, Richard Montgomery, got killed in the opening assault on Quebec. The second, John Thomas, died of smallpox, along with many of his men. Inoculation was possible, but, like today’s vaccine skeptics, many thought it a bad idea. You can visit the capacious cemetery for the victims on Île aux Noix, now Fort Lennox, Canada.

The third general, the most talented of the lot, was Benedict Arnold, who held the expedition together even after suffering a grievous leg wound. Eventually, however, he grew disgusted with a Congress rather less craven and incompetent than its contemporary successor and became a traitor, accepting a commission as a brigadier general in the British army and fighting against American forces.

We tried again in 1812. Thomas Jefferson, the original Republican, described the acquisition of Canada as “a mere matter of marching.” This was incorrect. The United States launched eight or nine invasions of Canada during the War of 1812, winning only one fruitless battle. The rest of the time, it got walloped. For example, General William Hull, like other American commanders a superannuated veteran of the Revolution, ended up surrendering Detroit with 2,500 troops to a much smaller British and Indian force. Court-martialed for cowardice and neglect of duty in 1814, he was sentenced to death but pardoned.

Secretary of Defense Pete Hegseth is perhaps unfamiliar with the Battle of Chateaugay. The last three letters are, after all, gay, and as such, the battle has doubtless been expunged from Defense Department websites and databases, meeting the same fate as the Enola Gay. Still, it is instructive. An invading force of 2,600 American regulars encountered about 1,500 Canadian militia members, volunteers, and Mohawks under a Francophone colonel, Charles de Salaberry.  They were defeated and had to withdraw.

Since the War of 1812, Americans have not tried any formal invasions of Canada, but there was tacit and sometimes overt support for the 1837–38 revolt of the Canadian patriotes, a confrontation over Oregon (a sober look at the size of the Royal Navy dissuaded us from trying anything), and the Fenian raids of 1866 and 1870. The Fenians were rather like the Proud Boys, only better organized and all Irish, and they also ended up fleeing back over the border.

Perhaps today’s Canadians are a flimsier lot. The Canadian armed forces are quite small (the army numbers only about 42,000, including reservists), although spirited and hardy. One should note with respect that 158 Canadians were killed fighting alongside American soldiers in Afghanistan. But even if the Canadian military were overcome after some initial bloody battles, what then?

Canadians may have gone in for wokeness in recent years, it is true, but there is the matter of their bloody-minded DNA. It was not that long ago that they harvested baby seals—the ones with the big, sad, adorable brown eyes—with short iron clubs. They love hockey, a sport that would have pleased the emperors and blood-crazed plebeians and patricians of ancient Rome if they could only have figured out how to build an ice rink in the Colosseum.

[Read: Canada is taking Trump seriously and personally]

Parenthetically, there remains the problem of the First Nations (as the Canadians refer to them), whom they treated somewhat less badly than Americans treated Native Americans (as we refer to them). There are about 50,000 Mohawks straddling the U.S.-Canadian border, and they are fearless, which is why you will find them building skyscrapers at terrifying heights above the street. As members of what used to be the Iroquois Confederacy, they were ferocious warriors, and they retain a martial tradition. It is sobering to consider that they may think, with reason, that we are the illegal immigrants who have ruined the country, and therefore hold a grudge.

There is a martial spirit up north waiting to be reawakened. Members of the Trump administration may not have heard of Vimy Ridge, Dieppe, the crossing of the Sangro, Juno Beach, or the Battle of the Scheldt. Take it from a military historian: The Canadian soldiers were formidable, as were the sailors who escorted convoys across the North Atlantic and the airmen who flew in the Battle of Britain and the air war over Germany. Canada’s 44,000 dead represented a higher percentage of the population than America’s losses in the Second World War. Those who served were almost entirely volunteers.

Bottom line: It is not a good idea to invade Canada. I recommend that in order to avoid the Trump administration becoming even more of a laughingstock, Secretary Hegseth find, read, and distribute to the White House a good account of the Battle of Chateau***. It could help avoid embarrassment.

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Whenever science has to defend itself from the skeptics, it tends to fall back on medical or other technological achievements that have improved our lives—such as the personal vehicle, solar energy, insulin, or ibuprofen.

Many scientists currently feel under threat to justify their research as the Eye of Sauron—sorry, DOGE—turns to the National Science Foundation and the National Institutes of Health, jeopardizing grants to university research programs. Some have tried to draw the link between the cuts and their harms to patients and medical progress. But much of science can’t build a one-to-one connection between the curiosities of researchers and the immediate needs of humanity. Does that mean it’s worthless?

On today’s episode of Good on Paper, I talk with Johannes Krause, who works at the Max Planck Institute for Evolutionary Anthropology as an archaeogeneticist and paleogeneticist. His research focuses on trying to uncover the mysteries of early human life-forms: Homo sapiens, yes, but also Neanderthals and other hominins.

The first hominins evolved in Africa and began to leave the continent about 2 million years ago. But, unlike today, Earth was home to many different forms of human life. Krause and other scientists are curious about Homo sapiens, or modern-day humans. Figuring out what made us so special requires figuring out exactly when we distinguished ourselves from our other upright, walking cousins.

Basically all of humanity is descended from people who left Africa and mixed with Neanderthals—but when? A study of a handful of very old bones revealed that Neanderthals and Homo sapiens were living and procreating with each other much more recently than anyone realized: just 47,000 years ago.

“We’re really driven by finding out new stuff,” Krause says, “trying to understand, in our case, where humans came from—What’s their kind of evolutionary course? How did they adapt? What makes humans humans? How are we different to other mammals? How are we different to other types of humans?—which is largely driven by curiosity and will not result directly in products that you could easily sell to your mother and say, Look—I did this research, and now we have a new vacuum cleaner, or something like that.”

The following is a transcript of the episode:

Jerusalem Demsas: There are only a handful of known venomous lizards in the world.

The Gila monster, found primarily in the American Southwest and Mexico, is one of them. Gastroenterologist Jean-Pierre Raufman analyzed animal venoms from various species, including the Gila monster. Raufman eventually discovered some intriguing molecules in the lizard’s venom, a discovery he declined to patent.

Other scientists took interest in the Gila monster, and, eventually, those molecules became the foundation for GLP-1 drugs, like Ozempic and Mounjaro. These drugs are best known for their help treating diabetes and obesity, but recent studies have raised hopes that they could address chronic kidney disease, reduce the risk of heart problems and even cognitive issues and addictions to opioids.

As David Deming recently wrote for The Atlantic, “You can imagine a member of Congress in the 1980s denouncing the NIH’s wasteful spending on useless studies of Gila-monster venom.”

[Music]

Today we’re talking about another unrelated line of research that defies even my attempts to find clear, practical applications for modern-day humans. My name’s Jerusalem Demsas. I’m a staff writer at The Atlantic, and this is Good on Paper, a policy show that questions what we really know about popular narratives.

My guest today is Johannes Krause. He’s a researcher with a Ph.D. in genetics, working at the Max Planck Institute for Evolutionary Anthropology. When early modern humans came out of Africa, at some point, they interbred with Neanderthals. The evidence of those unions are in the genes of most humans alive today. A paper Krause recently co-authored with several other scientists helps pinpoint when this happened. Figuring out this prehistoric mystery is one step towards understanding why Homo sapiens are the only form of human left standing.

Johannes, welcome to the show.

Johannes Krause: Yeah, I’m very glad to be here, Jerusalem.

Demsas: So in 2022, the Nobel Prize went to your colleague—and I hope I’m saying his name correctly—Svante Pääbo for determining that Neanderthals mated with prehistoric humans. In an interview, he said, “The last 40,000 years is quite unique in human history, in that we are the only form of humans around.” If, right now, you and I could travel back 40,000 years ago and take a sort of census of human Homo genus species, what would we find in different parts of the world?

Krause: So if we could travel back to, let’s say, 100,000 years ago, we would find at least three different forms of humans—and we can debate whether we call them “species.” We are careful just calling them “forms,” because species is a concept from biology, which has definitions. And there’s many different definitions of what makes a species.

There’s at least 25 concepts of what makes a species, and for some groups, they work, and for some, they don’t. So we’re careful. That’s why we call them forms. If you pay attention, we are also calling them only Neanderthals—some of those archaic humans, other forms of humans that existed—and not Homo Neanderthalensis, which would be this nice Latin term that has been introduced in the 18th century, which, again, comes with a certain species concept. So we’re trying to be a little bit careful and neutral, and just call them forms of humans.

So Neanderthals were one of them, which is probably the most famous one that most people have heard about. Then, of course, there’s us—modern humans. But then there were also other groups, like one that we discovered a few years ago that lived in Asia, the so-called Denisovans. They were named based on a cave where the bones were discovered in, where we got the first genome.

But there were also other types of humans that have been discovered based on fossil evidence. So for example, there was a group of humans that was called Homo floresiensis that lived in Flores, which is an island in Indonesia, probably until about 50,000 years ago, when the first humans came there. And there was also a group called Homo luzonensis, which was living in the northern part of the Philippines, on the island of Luzon. That’s where the name comes from.

So those are at least five different groups, then, including us. But there’s also some people that suggest there’s something called Homo malayensis, Homo daliensis, Homo erectus maybe still present in some parts of Southeast Asia. So there were a whole bunch—at least half a dozen, maybe even more—types of human forms that lived at that time, 100,000 years ago.

And then 50,000 years ago, we emerged on the scene. We came out of Africa, and we largely replaced most of them, for whatever kind of mystical reason. One of the big questions we have in evolutionary anthropology: Why are we the winners, basically, of that type of competition, and what do we have that all the other groups did not have?

Demsas: What sorts of things distinguish these different types of forms of humans from one another? I know there’s probably a lot, but we have an image of a Neanderthal in our heads, but early Homo sapiens also looked a bit different than we look right now as well. So what made us different from them and other types of humans?

Krause: So as geneticists, we can quantify the amount of differences, which is just counting the number of base pairs in the genome that are different between those, say, Neanderthals and kind of modern-day people, which is not a lot. So this is about 0.1 percent of the genome. So 99.9 percent—they’re identical in their genome to the people that live today or to modern humans that lived maybe even 50,000 years ago. So they share a common ancestor half a million years ago, Neanderthals and us. So at that time, we were one population, and then we started to get different and diverge from each other.

And over this time period of maybe half a million years, they also got morphological differences. So I think if we would meet them today, we would probably recognize they look a bit funny. They had pretty big eyebrows. They had a bit of a protruding nose. They were a bit more stocky than we are today. If they were sitting on the New York subway, some people have argued that maybe you wouldn’t even recognize them if they were wearing a hat and maybe just have some clothes. And there’s a lot of diversity in the world today of people that are a bit taller and a bit shorter and a bit more stocky. So in a way, it might even be something that you might not recognize. But if you really pay attention, then they would look a bit different.

Some people even say, you know, there are people with similar features, individual features that are still living today, because there is a lot of diversity in the world today. So you might have the individual characters that are found in the Neanderthals in people today but not in combination, basically, in one person, like it was back then.

But they were quite similar to us. I mean, we would have recognized them as people. We would say they’re humans. That’s also, when we talk about them—they’re humans. They’re not modern humans. They’re not us. But they’re humans, so they’re quite similar. And again, we’re 99.9 percent identical in our DNA to them. So they’re probably not different. They probably had some sort of language. Maybe if we would have tried hard, we could have also kind of communicated with them over time.

But then, at the same time, they must be different enough that there’s a reason that they are gone and we’re still here. They got extinct, so there must be something that we have that they did not have. Otherwise, I think all those other groups of humans would not have gotten extinct.

And that’s kind of part of the motivation, why we’re so interested in them, trying to understand what is different in us, because that kind of, then, also comes close to these questions, What makes humans humans? What is so special about people today? What’s so special about humans, in general? Why are we the dominant mammal on the planet? And maybe those archaic humans can actually help us to understand, because they, obviously, did not have what we have today, because, otherwise, they would be the dominant mammal on the planet.

And then what, basically, happened between them and us in this kind of short time period? We’re talking about half a million years between a common ancestor with them and us today, which sounds like a lot—half a million years. A lot of people would say, Wow, that’s a lot of time. But in evolutionary time, it’s a very short time period.

Demsas: So I want to turn to this study that you co-authored. And I absolutely love the origin story of this because I think it underscores just how random discoveries can be. Can you tell us about how your new project came about?

Krause: Yeah, it all started in 2020, when one of my colleagues, Hélène Rougier, who’s a professor at Los Angeles—she’s a paleoanthropologist, so she specialized in identifying little pieces of bone and kind of knowing whether those bones are human bones or whether those bones are animal bones—she was supposed to do a sabbatical, so spend a certain amount of time with us at our institute, in Leipzig, Germany. And she came, but then she was supposed to look at some bones from a site that we had studied, which was in the Czech Republic, where there were a lot of bones. The border was closed, so she couldn’t go to the Czech Republic. So we were like, Okay, what to do?

I mean, we’re sitting with her here. She can’t go anywhere. So I’m calling some of my colleagues from the neighboring cities, [seeing] if they have some boxes of bones that she could maybe look at from the past. And then one of my colleagues, Harald Meller, from Halle, the closest city to our city here, was like, We have those 120 boxes from a site in Thuringia, in central Germany, that were excavated in the 1930s from a site that’s called Ranis. And it’s, like, below a castle. It used to be a cave that collapsed thousands of years ago. And it was excavated in the 1930s, and they had to stop because World War II started, and then they, basically, put all the boxes somewhere in the basement, and no one really looked at those boxes for, like, a hundred years.

And then, we were like, Okay, sure. Hélène was very happy to have something to do. So we just got all the boxes here to the institute, and she spent three weeks looking into the kind of boxes. These were tiny, little bone fragments that were excavated from the, basically, Pleistocene—old layers from the Ice Age, thousands of years ago.

Mostly, those were animal bones, but she found about 120 bones that she thought could be human. And there were about 28 that she said—they were from a very old layer, because they were from boxes that were labeled from the lowest layer of the cave. And they said, That would be really cool because, based on the archeology that is associated with those old layers, they should be very old—very early modern humans, potentially.

And so we said, Okay, let’s analyze them. And we were not sure if they are modern humans, if they’re Neanderthals, and what kind of human they could be. And we sequenced the DNA, and—yeah—to our surprise, we, first of all, found they were not Neanderthals, but they were actually modern humans. And what was amazing was that we also dated them.

So we radiocarbon dated them, determined how old those bones were, and they were 45,000 years old. And they were, at that point, with that kind of radiocarbon dating that we had, the oldest human bones—modern human bones, the Homo sapiens bones—that we had available. And one of them, even, was the best-preserved bone from the Pleistocene, so from the entire Ice Age. We had a lot of human DNA, enough to do a very high-quality genome.

And then we did a whole genome analysis, and we found very old people from 45,000 years ago, from the site in Thuringia where we had genomic DNA that we could study. It turned out one was a mother and a daughter. And we also found that some of them were related by fourth, fifth degrees to each other. And what was even more amazing was that we had published, just a year before, a genome from a very old individual, from a female individual, from a site in the Czech Republic that’s called Zlatý kůň, which means, in translation, “the golden horse.” That’s the name of the mountain above the cave where it was discovered in the 1950s. Unfortunately, that could not be radiocarbon dated, but, based on the genetic analysis, we could already say this was a very old person, not in terms of age, but, like, how old that person lived in the past.

And it turned out that this individual was related to our individuals from Thuringia, from Germany, which is 300 kilometers away from each other, which was an amazing surprise. I mean, what’s the chance that you look at some Ice Age people from 45,000 years ago and you find the great-grand-cousin of that one person and the other person? We have 10 genomes, and they happen to be related, which is really incredible.

Demsas: It’s like putting your DNA into one of those databases now and, like, finding a relative who lives next door.

Krause: Exactly. What’s the chance, right? Or someone that you went to school with or something like that. It’s very unlikely, but here we go. We had a very close relationship, and we had complete genomes. And those genomes are really interesting to analyze, because they also turned out to have, still, very long chunks of Neanderthal DNA.

I mentioned it before—we could already show that about 15 years ago, we sequenced the Neanderthal genome at the time, and we also sequenced the genome of the Denisovans, of this other type of human that we then discovered. And when we looked at those genomes of those archaic people, we actually saw that all people outside Africa carry Neanderthal DNA today. And people in Southeast Asia carry the DNA of the Denisovans, so there was some gene flow between those other forms of humans and modern humans.

Demsas: So the first thing I want to jump in on is one of the big contributions of this paper, which is that we had learned that there had been admixture between Neanderthals and Homo sapiens. But you’re finding that this is happening much later than we had previously believed and that there’s this overlap of about 5,000 years when both human forms are coexisting. What is important about learning that?

Krause: So we actually found that, instead of some people saying it happened 50,000 to 60,000 years ago, it happened only about 47,000 years ago. And how did we find that? We found in our old genomes from Germany and Czech Republic that they carried very long chunks of Neanderthal DNA in those people’s genomes. They had the same admixture event that everyone outside Africa carries today. So people in Europe have that, and people in Asia have that. So they are part of the population outside Africa.

But they had very long chunks because, over time, the chunks become shorter. So when you have, basically, two people recombining—so a mother’s and father’s DNA recombining—then the chunks get shorter and shorter over time. But they had very long chunks, which told us when, actually, the admixture happened, because it’s like ticking off a clock.

So long chunks become shorter and shorter through time. So if you have longer chunks, you can actually calculate when the admixture happened, and we did that to about 47,000 years ago. So about 50 to 80 generations before our individuals lived—they had admixed with Neanderthals. And now this is the admixture that is common to all people outside Africa. So for the first time, we were able to say, This happened 47,000 years ago. Before, it was very indirect, using genomes of today. And there was lots of uncertainty when it happened.

And why is this important? It’s important because there’s hundreds, maybe even thousands of archaeological findings outside Africa that are attributed to modern humans, where people say, This was made by modern humans. This was a modern human skull. This was a modern human tooth. This is evidence of modern human presence outside Africa that is older than 50,000 years.

So there’s a lot of evidence for modern humans being present outside Africa before 50,000 years ago. But now we are saying that Neanderthals and modern humans only admixed 47,000 years ago, and everyone outside Africa has the Neanderthal DNA, so it’s basically not possible that modern humans—at least, how we know modern humans today: Europeans, Asians, Australians, Aboriginals—that it has to be, then, a different type of modern human, because all the modern humans today go back to a common ancestor that left Africa or intermixed with Neanderthals only about 47,000 years ago. So everything that’s older than 47,000 years ago has to be made by someone else. Or if it’s a bone, it has to be someone else.

And that’s very important because there really have been a whole lot of different studies published in highly prestigious journals over the last few years for evidence of modern humans being present in Papua New Guinea 60,000 years ago, modern humans being present in Australia 60,000 years ago, modern humans being present in Vietnam 70,000 years ago, modern humans being present in China 100,000 years ago, 80,000 years ago, 70,000 years ago.

And basically, all of that is, then, not us. It’s, basically, not the people that we know today outside Africa, because all of the people today outside Africa are from that common-ancestor population that we were now able to date to 47,000 years ago. And that’s quite important. So this is basically now dating, if you want, the “out-of-Africa event,” because that is, really, the last point that all people outside Africa were a common population, because we all share the admixture with Neanderthals that we could now date. So therefore, it’s really important for human evolution to understand when that happened, because it gives us a common ancestor of all the people outside Africa.

Demsas: And I want to make sure that listeners fully understand why you’re distinguishing outside of Africa versus what’s going on there. Can you expand on that?

Krause: So humans evolved to modern humans, Homo sapiens. We evolved in Africa. So of course, our entire lineage evolved in Africa. So the first kind of upright, walking, early hominins evolved probably 7 million years ago. And then about 2 million years ago, the first hominins left Africa. So Homo erectus left Africa, came to Europe, Asia, evolved into different types of Homo erectus.

So there were different types of humans—I call them humans—so hominins outside Africa, and that then includes also Neanderthals, Denisovans, the different forms that we talked about. But then, 50,000 years ago, we had the emergence of Homo sapiens, modern humans. So we left Africa about 50,000 years ago and went outside Africa.

And this was something that, of course, is a major event in human evolution. So something that, basically, gave rise to the human diversity that we have on the planet today. Part of that, of course, is that the people that left Africa were not everyone leaving Africa. It was just part of the genetic diversity. It’s just a part of that population. People even calculated: It’s only about, probably, between 5,000 to 10,000 people that left Africa. So there is more genetic diversity that’s left behind in Africa, which is also reflected today. Just looking at the genetic diversity, there is more genetic diversity in Africa than outside Africa.

There is, basically, larger genetic diversity present. So if you compare the genomes of two people from somewhere in Africa, you have an average of about 6 to 7 million differences in the genome, whereas if you do that for people outside Africa, you have 4 to 5 million differences in the genome. So there is, basically, more genetic diversity, which is part of that story, because just part of that population left.

And then when people came outside Africa, about 50,000 to 47,000 years ago, as we now know, they met Neanderthals because they’re there. They’re outside Africa. They’re probably somewhere in the Middle East. They’re probably somewhere in the Levant, so modern-day Israel or Lebanon or Jordan. And there, they meet Neanderthals; they mix with Neanderthals. And from there, they expand into Europe, Asia, Australia, later on into the Americas. And they take this Neanderthal mixture with them. And that is a really big event that we’ve known about for 15 years now, but we didn’t know when it happened, and now we do know when it happened.

Demsas: One unexpected finding in your study that you flagged for us earlier is the familial relationships that you’re finding between individuals who are pretty far apart. There’s one that I remember that was about 230 kilometers, or roughly 140 miles, apart. You also find that there’s a pretty small population, and you’re estimating these early populations as numbering only in the hundreds. So first of all, how are you doing that? How are you figuring out what the population size is? And given that it’s a pretty small population, is it surprising to find familial relationships among the fragments that you’re finding today?

Krause: So it is not completely surprising that we find closer relatives to the small population. So of course, if you go into a rural region somewhere in the world and you kind of sample people genetically, then it’s a higher chance that they are closely related than if you take that in New York City, where there are millions of people living. It’s basically a result, also, of the small population that we find so many relatives.

How we do that, how we can actually measure that, I mean, how we look at relatedness is how you do it today, how companies are doing it. You send the DNA to just compare the genetic profiles and see how much is identical, how much is different. And from that, you can measure how much relatedness you see between two individuals.

But what you can also do is, to calculate, for example, population size, you don’t compare the genome of one person to the genome of another person, but you actually compare the genome that you get from the mother and the father within the person, because you actually have two genomes, right? You do not have just one genome; you have two. You have to have two copies of chromosome 1, two copies of chromosome 2, two copies of chromosome 3, and so forth.

So if you compare those two to each other, if you have a very large population, you expect that on almost every part of the chromosome, there are differences between mother and father. But if it’s a small population, there happens to be, by chance, regions in the chromosome that come from a common ancestor quite recently. Because in a small population, you don’t have much choice with whom you can have children. And therefore, it’s often the chance that you have children with someone who’s actually not too far related from you.

And that basically causes regions in the genome that are identical, where both chromosomes are identical. They come from a common ancestor. And this happens in small populations and doesn’t happen in large populations. So you can directly calculate, basically, what that means for the population size. And then we came to a calculation of about 100 to 300 individuals. So that’s quite small because we’re talking about the region that stretches from the British Isles, which were, at that time, connected to Europe, and Poland. So it’s a large region. It’s, like, thousands of kilometers, only a few hundred people.

I mean, imagine that, right? Today we have a billion people living in Europe. And at that time, it was maybe just a few hundred people living in Europe, which is really insane. But then, of course, if you then happen to just find some of them, there’s a good chance—if you find them, by chance—that they are actually related, because there were just a hundred of them. It’s like an extended family, basically. So if it’s from the roughly same time period, then there’s a good chance you’ll find relatives, and that’s exactly what we found.

So we have basically two lines of evidence: First, the finding that we have relatives is expected if it’s a small population, but also, within the genomes of those people, we see that there were not a lot of people living at that time.

Demsas: So given that there was this interbreeding happening between different hominins that you’re finding in your research with Neanderthals, do you expect to find the same sorts of things with other types of human hominins mixing in other parts of the world?

Krause: We have actually seen that. We have found, already, 15 years ago, when we sequenced the first genome of the Denisovan, this other type of human, which jumped out of a box. It was like a super big surprise that we found in the lab a new form of human. If you think about that, when you do an excavation, you dig somewhere, and you find a skeleton, a fossil. You’re like, Wow, amazing. We found a new type of human, but imagine that happening in the lab.

I was the lucky person to discover it some years ago. And I was busy working in the lab. I looked at DNA sequences and looked at them on the computer and was like, Wow, this is not Neanderthal. This is not modern humans. That’s something else. It’s a new form of human. It’s incredible, right?

And when we then sequence the genome of this new form of human, we also found that it’s distinct to Neanderthals, it’s distinct to modern humans, but it’s actually more of a sister group of Neanderthals. It’s a bit closer to Neanderthals than it would be to modern humans. It separated from Neanderthals about 300,000 years ago, but there are also some populations of modern humans today that carry some of that DNA, some ancestry from those Denisovans.

And that includes groups in Papua New Guinea, in the highlands—so Indigenous groups from Papua New Guinea and also Indigenous groups from Australia. So Aboriginal groups carry about 5 percent of their genome from this Denisovan group. And there’s also some group in the northern part of the Philippines that has about 7 percent from those Denisovans.

In fact, colleagues of mine have shown that there were at least five admixture events between Denisovans and modern human groups in different parts of Asia. So people in China and in Japan, for example, have different ancestry from Denisovans than the people on Luzon, in the Philippines, and yet, a different type of Denisovan ancestry in Papua New Guinea and Australia. So they interacted multiple times.

And that’s different to the Neanderthals. For the Neanderthals, we have one main event that is shared with all people outside Africa, but then we also have some local events where we have local people—for example, some individuals that were found in Romania, some people that were found in Bulgaria that lived 42,000 years ago or 40,000 years ago—they had additional Neanderthal ancestry, so they had also admixed with additional groups, but they actually went extinct. They did not leave descendants. They did not give that DNA to people that live today. And so, therefore, today, all the people outside Africa only carry that one pulse of Neanderthalic mixture that’s basically shared with all the people outside Africa.

But in East Asia, Southeast Asia, it’s different for Denisovan DNA. So people from China or from Japan, for example, have different Denisovan DNA than people living in Papua New Guinea or Australia. So there have been multiple events that are still present in the diversity of people living in those parts of the world today.

[Music]

Demsas: After the break: the ancient human genomes we’ll never get to learn from.

[Break]

Demsas: One thing I want to ask you, broadly, about this research is about selection issues. Obviously, you need some level of preserved remains in order to do this sort of analysis, and most of these are found in very cold regions of the world or are things that can be fossilized and maintain their structural integrity to some extent. Are you worried about how that might bias findings about this time period in history?

Krause: Absolutely. That is a strong bias. So in fact, we have a very hard time finding ancient human genomes from, say, equatorial regions. So places that are really warm in average temperature, people that are moist—they don’t preserve DNA well like northern latitudes, because it’s just too warm.

The preservation is not good enough. We cannot go back to 50,000- or 100,000-year-old humans from Africa, which is unfortunate because there’s, as we said earlier, more genetic diversity. This is where humans evolved. That’s where the really interesting stuff is happening. But that’s actually where we don’t have a lot of ancient DNA. We cannot really go back.

I mean, there’s some genomes—there’s one, actually, from Ethiopia, which is about 5,000 years old. There’s some, again, from Morocco. There’s some from Malawi that are even older than 10,000 years. So there is some ancient DNA maybe going back to the last 10,000 or 15,000 years in Africa, but we cannot go back 50,000 or 100,000 years, or maybe even more time ago, whereas, for example, in Europe, the oldest human genome that has been analyzed so far by my colleagues here at the institute is 400,000 years old—so almost half a million years old from a site in Spain, in Sima de los Huesos, which are some early Neanderthals, it turns out, genetically.

It was also very exciting to find those early Neanderthals there, because it means that Neanderthals are at least 400,000 years old, which is also something that wasn’t actually clear. So they’re already on the Neanderthal lineage after they have diverged from the Denisovans and from modern humans.

Demsas: One big question that you raised in the top for us is this large mystery of why it is that Homo sapiens won. And there’s this general sense that I think we’re taught in K–12 here when learning about this time period in history, which is that Homo sapiens were just better. We were, for some reason, just a superior form of human and were able to outperform and outlast all of these other forms of hominins. Can you tell me what the kind of prevailing wisdom is about why this happened?

Krause: There’s a whole bunch of different hypotheses, and I summarize some of them in a book that we just published—actually, just a couple of weeks ago in English—that’s called Hubris, where we talk about the history of humankind, so the rise and fall of humankind and, also, the kind of challenges that we have in the future and looking into the past.

So the big hypothesis we’re talking about is: What makes us special? What do we have that they did not have? And I mean, there’s much speculation in that direction. So what we can see is that modern humans are extremely expansive in their nature. We are expanding very fast. We basically don’t tolerate, sometimes, borders—like, to a degree where it’s almost suicidal.

If you think about going on a little raft into the ocean to discover an island, like, 3,000 kilometers away in the middle of the ocean, who would ever do that? Like, what the hell? What kind of drives people to go on some of those kinds of crazy adventures to discover new land? I mean, even sitting in a rocket that shoots you to the moon—why would someone do that? But we are doing those things. We are adventurous, in some ways.

Our population is highly culturally diverse, and we adapt surprisingly fast to different environments. We are living in all ecosystems you can imagine on this planet, from high altitudes to deserts to living on the ocean or living in the Arctics—which, also, no other mammal has like we have, because, culturally, we have a high plasticity, so we can really adapt super fast, which is also something that we don’t really see to that extent with other earlier human forms.

And our population has been growing surprisingly fast through time. So we have a lot of children. That largely come out of later time periods, when we start with food production. So with agriculture and pastoralism, then we basically produce food in large amounts, and then the population becomes billions of people, like we have today, which is a process that happens later, after we came out of Africa.

But it’s part of the success story and also shows—and this is something where we conclude, also, in this recent book that it should have a biological basis, what I’m now talking about—that agriculture and this kind of complex way of food production actually emerges in parallel in at least five different places in the world, starting about five to 10,000 years ago.

So there must be something that modern humans had that allowed us to develop this complex way of life—food production, domestication of plants and animals—that happens independently so many times. It didn’t happen in the hundred thousands of years before, even when climate was similar and stable. But about 10,000 years ago, there is something in the kind of genetic makeup of the people that came out of Africa 50,000 years ago that we seem to have all in common, that allows us to develop this complex way of life, which I don’t think was there hundreds of thousands of years ago.

So that’s really something that is unique, which kind of tells me that there must be a biological basis to that—that something evolved in Africa more than 50,000 years ago that allowed us to expand out of Africa, to be, in a very short time, basically, replacing all other forms of humans. I mean, we were talking about 5,000 years, and all those earlier forms—Neanderthals, Denisovans, Homo floresiensis, Homo luzonensis—all those groups were extinct, and we’re the only ones left behind. And then we came up with this incredible way of living and complex culture. We settled all kinds of distant places, the tiniest islands in the Pacific in that short time period of about 50,000 years, the entire planet. There needs to be a biological basis to that. I cannot imagine that this is just pure coincidence.

But we can’t point it now to one gene. We can’t really say, It’s this gene. It’s that gene. Maybe it’s a number of different genetic changes that happen. If you compare the genome of a Neanderthal to the genome of a modern human today, it’s a surprising kind of similarity—as we said, 99.9 percent. But even if you just look at the specific differences, like how many genes are fixed differently between Neanderthals and modern humans, there’s less than 100 genes that are different between a Neanderthal and a modern human.

But somewhere there, I think—and maybe a combination of several of them—hides exactly that type of mystery of what we have and they don’t. But that’s what we’re still after, right? So even if we now have a Neanderthal genome and some of those other earlier genomes, we haven’t really found yet the exact recipe—basically, what makes us so special. But I think we’re getting much closer to that than we were 10 years ago, before we had those genomes of those archaic humans.

Demsas: I know this is an area of research where just learning and understanding on its own terms is important, but I think that there are also some really interesting implications for modern-day humans. I came across this study that found that a major genetic risk factor for severe COVID-19 was inherited from Neanderthals. Can you explain how that was found?

Krause: So this was my colleague Svante Pääbo here at the institute. He found that, together with another colleague, Hugo Zeberg, from the Karolinska Institutet, in Stockholm. And what they made use of was a large study and effort from another group from Helsinki in Finland, called FinnGen. They collected patients’ genomes from COVID-19 and looked at severe cases and looked at their genetic factors that cause a stronger response or higher risk of actually having severe COVID compared to others.

And they did find regions in different parts of the genome that gave a higher risk. Interestingly, the kind of regional chromosome 3 that has the highest risk to actually have a severe form of COVID and have a three-times-higher risk to actually die of it was then found by Svante and his colleague Hugo to come from Neanderthals. So basically, they just made use of someone else finding all those regions, and they looked, like, Could that be from Neanderthals? And it turns out to be from Neanderthals.

It’s somehow a bit of a fun fact, to some degree, because it’s not really. So okay, now we know it’s from Neanderthals. That doesn’t help us to cure COVID or to do something about the disease. It does not. But it does tell us, then, of course, that this is something that actually came into the human population about 45,000 years or 47,000 years ago, when modern humans and Neanderthals admixed. It’s not found in Africa. It’s found outside Africa only because it came from Neanderthals when they admixed. It’s in high frequency in southern Asia. It’s in higher frequency in Europe.

So it points out a bit more the history of this interesting region. And what kind of story might be behind it probably has something to do with some other diseases, which are not coronaviruses but probably some other diseases that have caused this variant to be, for example, in high frequency in South Asia. So my colleagues are now studying it and trying to understand the exact mechanisms that are actually behind this more severe form of coronavirus.

And there are many other such examples where we have found that Neanderthals passed on some of their genes to us, which were, actually, good for adapting to certain environments. So for example, immunity genes that help us to tackle some of the pathogens present , probably, in Europe at the time when they came here. There’s also some genes, like a gene that people have in East Asia today, that allows them to live in high altitudes. So for example, Tibetans, like the Sherpa, which are this famous group of people living in Tibet today—almost all of them carry a gene that came from the Denisovans into the gene pool of East Asians.

Whereas the frequency in an average person from East Asia is only about 0.1 percent of the gene, Sherpa have it to 100 percent. They all have it. So it was very advantageous to have that gene. And it came from Denisovans, and we do know now, even, that Denisovans lived in high altitudes, because in some cave in China, they found a bone that is from a Denisovan. We know that now genetically, as well as based on the morphology. And that was found at 3,200 meters altitude. So they actually lived already for a long time in high altitudes and were probably, over time, adapted to live in that high altitude. And that helped the people like the Sherpa today to live in Tibet, which is quite useful.

It’s a bit more kind of a complex mechanism, what it’s actually doing. It’s actually switching off the natural adaptation that all of us have when we go to high altitudes, when your body starts to adapt to the kind of low oxygen levels. And basically, those Sherpas switched that mechanism off, so it’s not working anymore. But for living at high altitudes for a long time, it’s actually what you need. And that’s an interesting example of something that we actually inherited from those archaics and gave us something that kind of made life for people better.

Demsas: I feel like I want some more context on how different this can lead modern-day humans to be, because there’s tons of mixture that’s happened between the populations of Europe, Asia, the Middle East, Africa, the Americas. There’s tons of intermarrying and children that have been had. Is it just that there’s such a short time period where that’s been happening, where you still see serious differences in the genetic codes of people in Tibet versus Central Europe, like you said?

Krause: Yeah. So this is indeed the case. So populations in some parts of the world have it mixed more. In some parts of the world, they have it mixed less. Like, the genetic differences between European populations are half as strong now than they were 10,000 years ago, because over the last 10,000 years, humans in Europe merged with different parts.

There was a whole group of people coming with agriculture from Anatolia. About 7,000 years ago, there was another group coming from Eastern Europe. But then there are other parts of the world where populations have been more stable, like Inuit, for example, in northern America. They have been pretty un-admixed in the last 4,000 years. But even there was some mixture, and there was some replacement with some other groups.

And this is, in a way, if we wouldn’t have modern medicine and technology, the environment still has a very strong selection on people. So one good example that I always tell my students is: Australia. Australia today has, by far, the biggest rate of skin cancer in the world. Why is that? Because they largely come from Great Britain and Ireland. That’s where most of that population descends from. They moved to almost the equator. They moved to an environment that they’re actually not adapted to.

They come from Northern Europe, basically, to equatorial regions, where the sun is very, very intense. They should have dark skin, like the Aboriginal population in Australia that has dark skin. They don’t have skin cancer, because they are adapted to living in latitudes on the equator, whereas Northern Europeans are not. It’s not so much a problem today, because you have sun blocker; you have all kinds of medical treatments. So it’s not a strong selection pressure anymore, but if you would give it a natural thousand years or 2,000 years, basically all Australians would look like Aborigines, because their skin would just adapt over time to living on the equator. And that’s a natural tendency that happens everywhere in the world.

So you have Native Americans, for example. So Native Americans in North America and far in South America—they have lighter skin than the ones living in Bolivia or Ecuador, living on the equator, because they had to adapt. They actually came with lighter skin to the Americas, and then they started to live in high altitudes, as well as on the equator, and got darker skin. So this is also a natural kind of tendency to adapt to living in equatorial regions.

And there are, of course, many other such examples. It could be the environment, like sun exposure, but it can also be a diet, right? So in Europe, for example, there is this lactase persistence, which a lot of people have. So a lot of people in Europe can drink 2 liters of milk, which the majority of people in the world cannot do. But 5,000 years ago, people started consuming milk. Probably 3,000 or 2,000 years ago, that peaked and caused a variant to emerge that gave people the ability to drink a lot of milk in adulthood, which mammals usually don’t have, because no mother wants to breastfeed the offspring for the rest of their life. They want to get rid of that.

So what Mother Nature did in evolution was to switch the gene off that allows us to digest milk, which is the lactase gene. So for normal people, that switches off, which is good. That happens with your cat. That happens with your dog. That happens with any mammal out there. But then for humans, they started to drink a lot of milk because they had cows. So they used cow milk. But then it is bad if you have that gene switched off, because you get all kinds of problems.

But then, people had a mutation that allowed them to drink a lot of milk, which was extra proteins. And then they adapted, and that’s adaptation, now, to the food but not to the environment, but basically the kind of environment that we have created. So this is something that is also part of that story. The local adaptation is something that, of course, different environments and, also, different types of foods are introducing.

Demsas: So I have really pushed to try to figure out a practical application for modern-day humans in this debate and in the research strain that you’ve been pushing on. And I was reflecting about why I was trying so hard to find that, and it probably has to do with the larger debate that’s happening in the U.S. right now about the value of research that does not have an obvious direct material benefit to people.

We’ve talked a little bit about how it can help us understand genetic risk factors and understand the way that we can metabolize different foods, and you’ve walked us through that. But I largely categorize the research you’re doing as interested in uncovering the truth about who we are and how humanity came to be divorced from immediate practical considerations. How do you make the case to people about the value of this type of research?

Krause: So I’m working in the Max Planck Society, and we do basic research. So we are not driven by what can be turned into a product, what’s applicable to some sort of new medical treatment, or what is something that will really benefit humanity directly, as some new discovery that will result in a new form of energy or a new form of medical treatment or so.

We’re really driven by finding out new stuff, kind of basic research, trying to understand, in our case, where humans came from—What’s their kind of evolutionary course? How did they adapt? What makes humans humans? How are we different to other mammals? How are we different to other types of humans?—which is largely driven by curiosity and will not result directly in products that you could easily sell to your mother and say, like, Look—I did this research, and now we have a new vacuum cleaner, or something like that, right? This is maybe what a physicist or mechanic can do but I cannot do.

But then, a lot of people are interested in ancestry. A lot of people are interested in history. A lot of people are interested in evolution and trying to understand how things evolve. And in my case, I’m also doing a lot of work. About half of my work is, actually, not on the evolution of people but on the evolution of pathogens. So where did some of the most infamous pathogens in the world come from? Plague, leprosy, syphilis, tuberculosis, and so forth. And there, I could even come up with this being relevant, because we try to understand where pathogens emerge, how they change, their evolution trajectory, their mutation rate. So I do have some examples where I could say that could be relevant, also, for medical research in infectious-disease biology.

But in terms of human evolution, I think it is largely curiosity driven. And I think there’s also what our society, the Max Planck Society, stands for—that we really want to create more basic research and try to understand various kinds of things that should be researched and should be understood. And I think that’s an incredible luxury to have, I should also say, especially in these times that we’re living today, where a lot of people question, Why should we do research, right? Why should we spend money on that? We need to save money for something else, either for defense or for certain products or certain luxury goods or just, even, for food or for health for a lot of people that are maybe marginalized in certain parts of the world. But you can also never know what your discoveries, your basic science and insights, might actually generate in the future.

Demsas: So what you were saying about what drives you to do basic research really reminded me of the same exact thing you said earlier about what may have made Homo sapiens special: this kind of desire to explore and research and find new things, even if there’s not a very clear, obvious reason to do it. Like, why strike out to go see if that island is habitable? Why look to see who your ancestors are? I mean, these are questions that maybe other mammals wouldn’t investigate, but it maybe is what makes us different.

But I think this is a great place to ask our last and final question, which is: What is an idea that you had that you thought was a good idea at the time but ended up being only good on paper?

Krause: That’s hard for me. I mean, you have all kinds of experiments that you do in the lab, and that’s almost on a weekly basis where you say, We should do this. We should do that. For example, in my first book that I wrote some years ago, Short History of Humanity, we speculated that horses, when they were domesticated, were responsible for the spread of plague. Now, that sounds crazy, but we had some reasons to think, because horses are partially immune to plague, that they played an important role, because at the point when horses got domesticated, the plague spread for the first time.

And we thought that there’s some sort of a correlation here, and that might also explain why horses are more resistant to plague than other animals. At the end, what we actually could see from some of the data that wasn’t generated by some of our colleagues, together with us, was that horses were domesticated a thousand years after the plague spread. So, okay, bada boom. That kind of hypothesis is then not substantiated. And that, of course, happens often in science, where you come up with a hypothesis, and then you reject it. So that’s quite normal.

If I think about stories that kind of made me really excited over the last 20 years doing research, one thing that I was really hoping for is longevity and extension of longevity. There was much debate when I was a student: The first human genome was deciphered, and now we can read it like a book, and we can switch off certain genes. We can extend the ends of the chromosomes, called telomeres, that will help us to become hundreds of years old. And being aware of mortality is one of the hardest things about being human, that kind of sucks. I wish to be a chimpanzee sometimes, and I wouldn’t be aware of mortality as much as I am, because I’m a human.

Demsas: (Laughs.)

Krause: Because it sucks if the lights turn off and that’s it, right? It’s gone, right? That was life. So longevity was something I was really excited about, but I haven’t seen any progress in that direction over the last 20 years, despite the big revolution we have in genetics and in molecular biology. So we don’t really see that people get older and older. And we eventually are still all gonna die. So that really, really sucks.

Demsas: Well, hopefully someone one day is studying our genomes in the same way you’re studying our ancestors. But, Johannes, thank you so much for coming on the show. I really enjoyed talking with you.

Krause: It was really great to be on the show.

Demsas: Good on Paper is produced by Rosie Hughes. It was edited by Dave Shaw and fact-checked by Ena Alvarado. Rob Smierciak composed our theme music and engineered this episode. Claudine Ebeid is the executive producer of Atlantic audio. Andrea Valdez is our managing editor.

And hey, if you like what you’re hearing, please leave us a rating and review on Apple Podcasts.

I’m Jerusalem Demsas, and we’ll see you next week.

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Sometime on Tuesday evening, the USAID website was taken down and replaced with what looked like a beta page from the internet of the 1990s. There were no affecting photos of American government officials distributing food and medicine overseas. Instead, a box of text explained that nearly all USAID personnel would be placed on administrative leave, globally. With administrative assistance from Elon Musk, President Donald Trump seems to have wiped out the world’s largest donor agency in just a few days. It was a radical act, but maybe not as politically risky, in the domestic sense, as other plans in the grand project of dismantling the federal government. USAID has important beneficiaries, but most of them are not Americans and live overseas.

In this episode of Radio Atlantic, we discuss where Trump and Musk seem to be headed and the obstacles they are likely to encounter in the future. What happens when Trump starts to face challenges from courts? What happens when Musk goes after programs that Americans depend on, particularly those who voted for Trump? What new political alliances might emerge from the wreckage? We talk with staff writer Jonathan Chait, who covers politics. And we also talk with Shane Harris, who covers national security, about Trump’s campaign to purge the FBI of agents who worked on cases related to the insurrection at the Capitol.

“I think that will send a clear message to FBI personnel that there are whole categories of people and therefore potential criminal activity that they should not touch, because it gets into the president, his influence, his circle of friends,” Harris says. “I think that is just a potentially ruinous development for the rule of law in the United States.”

The following is a transcript of the episode:

Hanna Rosin: Today is the deadline for some two million federal employees to decide if they want to type resign in response to the now infamous “Fork in the Road” email. The email, of course, is one in a list of things that Elon Musk, empowered by President Trump, has been doing in order to “disrupt” the federal government.

Donald Trump: We’re trying to shrink government. And he can probably shrink it as well as anybody else, if not better.

Rosin: For example: gain access to the U.S. Treasury’s payment system—

News anchor: Treasury Secretary Scott Bessent reportedly granting Elon Musk’s DOGE team access to the federal government’s payment system, which handles trillions of dollars in payments.

Rosin: —dismantle USAID, of which Trump is not a fan—

Trump: And we’re getting them out. USAID—run by radical lunatics.

Rosin: —and neither is Musk.

Elon Musk: If you’ve got an apple, and it’s got a worm in it, maybe you can take the worm out. But if you’ve got actually just a ball of worms, it’s hopeless. And USAID is a ball of worms. There is no apple. And when there is no apple, you’ve just got to basically get rid of the whole thing.

Rosin: All of these efforts are unusual, maybe even unprecedented, norm-breaking—even for Trump. But are they unconstitutional? And could they fundamentally change the character of the country?

This is Radio Atlantic. I’m Hanna Rosin.

[Music]

News anchor: At the FBI, some agents have started to pack up their desks as fears of mass firings grow.

Rosin: In the second half of the show, we’re going to focus on a special case inside the government, which presents a different set of potentially history-changing problems—the FBI—with staff writer Shane Harris.

But first, we are going to discuss what’s at stake, more broadly in this overhaul, with staff writer Jonathan Chait, who covers politics for The Atlantic.

[Music]

Rosin: Jon, welcome to the show.

Jonathan Chait: Thank you, Hanna. I’m delighted to be here.

Rosin: So, Jon, of all the unorthodox things that Trump has authorized Elon Musk to do with the federal government, which one strikes you as pushing constitutional limits the most?

Chait: Attempting to eliminate or cut spending for agencies that have been authorized by Congress. This is just a totally revolutionary step in terms of the structure of our government. And it’s kind of shocking, to me, how far he’s been able to go, and how much permission he’s received from the Republican Party.

Rosin: And is there another time in history when a president tested this limit between what Congress authorizes and what the president can do with that? And how has it worked out in the past?

Chait: That’s a great question. You had a struggle with Andrew Jackson over the Bank of the United States. That was a real constitutional struggle between him and his enemies as to how much power the president had vis-à-vis Congress and whether the president had just total authority to do what he wished. And Andrew Jackson was sort of known for pushing the boundaries of the office to or past their limits, and saying if the Supreme Court ruled against him, he would just do what he wanted, anyway. He did the same thing with his attempts to ethnically cleanse Native Americans to take their land. He just fundamentally didn’t care if he had authority from Congress.

That’s the kind of struggle we’re, I think, heading into right now. And Richard Nixon tried a smaller version, I think, of what Trump is doing now. He basically said, Congress has authorized certain kinds of spending, and I’m just going to impound it. But the Supreme Court ruled against him, and Congress passed the Impoundment [Control] Act that formalized the fact that Congress has this authority, and the president doesn’t, and if Congress authorizes spending, with very limited exceptions, the president has to carry it out. And if the president objects to certain forms of spending that Congress enacted, he has to persuade Congress to pass a law to change it.

Rosin: Got it. Okay. So that’s the line we’re working with. So it’s the Impoundment Act. It’s been defined by the Supreme Court. Can we talk about examples of, say, how far an administration can go in resisting a previous administration’s policies, but not pushing against this constitutional line? What would be something we’ve seen before? And what would prompt what people would refer to as, say, a legal or constitutional crisis?

Chait: Just in the big picture, the executive branch has been asserting more and more authority, over decades, as Congress has gotten more and more dysfunctional. The use of the filibuster has risen. Congress has gotten less and less able to fulfill its constitutional obligation to really direct national policy the way the Constitution imagined it. And so the executive branch has really kind of filled in this gap in a lot of ways. So you’ve seen presidents of both parties creatively exerting their authority.

You had Trump doing this with immigration, where he, you could say, couldn’t or just barely even tried to get Congress to fund the wall that he wanted. So he just basically redirected funding from the Pentagon to the border by calling it an emergency. And Trump is doing the same thing with tariffs.

Now, Congress basically ceded the president emergency authority to declare tariffs for various national-security emergencies, thinking that this would just be used in the case of something like a war or an international conflict, but it let the president decide what an emergency is. And so Trump can just say, well, an emergency is whatever he wants, and that’s on Congress.

And Biden has kind of pushed the limit in a lot of ways, I think most controversially with student loan forgiveness, where the executive branch has control over student loans, and so Biden just kind of forgave those loans on a kind of sweeping basis. Now, he was challenged legally. But when you’re in power, your party has a pretty strong incentive to interpret executive power in the most sweeping way.

So there’s a way in which both parties have really been engaged in this, but I really think what Trump and Musk are doing now has totally breached the walls of normal and is just turning the Constitution into a farce.

Rosin: Okay. So the reason that’s true is mostly because of appropriations? Because from what you’ve said, presidents are pushing this line constantly. So what are they doing that doesn’t just break norms or traditions, but actually is pushing into constitutional crisis?

Chait: Article I of the Constitution, which is really just, like, the guts of the Constitution, says that Congress has authority over spending.

So Congress establishes an agency. Congress sets its spending levels. And throughout our history, with the exception we’ve described for Nixon, which was slapped down, the presidents have to follow that because that’s the law, right? Now, the president has a role in that. The president can veto some of these laws. If Congress proposes spending that the president doesn’t want, the president can veto it, and then Congress can override it, or Congress can make a deal with him. But whatever emerges from that is the law, and the president has to follow the law.

Rosin: Okay. And does the Trump team have any creative arguments for how to get around this Impoundment Act?

Chait: So far, Elon Musk is just operating in this totally chaotic legal gray zone. So his first target has been the United States Agency for International Development. And one thing they’ve made this argument is that, Well, that was just established by an executive order by the president, John F. Kennedy, 1961, so it can be ended by an executive order. The problem is: After it was established by executive rule, it was later established by Congress. Congress voted to make the United States Agency for International Development an agency.

So after Congress established the United States Agency for International Development, it had the force of law. And so saying, We’re going to eliminate this agency, is just a violation of the law. It’s pretty simple.

Rosin: Okay. I can see the argument. So can we play out both scenarios? The first scenario is: The courts push back on Trump. You know, they enforce the Impoundment Act. They say, You cannot do this. You can’t end USAID. Elon Musk has to stop roaming around the federal government and making these decisions that violate this constitutional balance of power. What happens then? Does it call Trump’s bluff?

Chait: It might, but I wouldn’t count on it, for a couple reasons. Number one: Musk is moving much faster than the legal system can move. And it’s a lot easier to destroy something than it is to build something. So once you’ve basically told everyone they’re fired, and they can’t come to work, they can sit and wait for the courts to countermand that while they’re losing their income and their mortgage is going under, or they could just go find another job somewhere.

Rosin: I see. So it’s just, like, facts on the ground change, so that even if the legal reality doesn’t budge, you’ve already disintegrated the actual infrastructure.

Chait: You lose the institutional culture. You lose the accumulated expertise. And by the time the courts have stepped in, rebuilding it is difficult to do, even if the president wanted to. And obviously, they’re not going to want to anyway. Second of all, it’s not totally clear that they’re going to follow the law, that the law has any power over them.

I mean, remember: Donald Trump established on the first day of his administration that he believes that people who break the law on his behalf can get away with it when he pardoned the entire—or commuted the sentences of the entire—insurrectionists, right?

Rosin: Yeah.

Chait: So Elon Musk knows full well that if he violates the law, Trump is going to have his back. So I think that’s also shaping the behavior of everyone involved in this episode.

Rosin: Right. So it sounds like you pretty strongly believe there is no brake to this. b-r-a-k-e. There is no stop to this. I was thinking that maybe the courts or something to, you know, put some hope in to stop this. But it sounds like no.

Chait: Well, in the long run, the courts can have an effect by saying, You don’t have the authority to eliminate this agency. It still exists, meaning that when the Democrats win back the presidency, if that ever happens, it’ll still be there, and then they can actually rebuild it.

Rosin: So in other words, in that scenario, there’s temporary dismantling, but the balance of powers remains in place, is affirmed by the courts, and things get slowly rebuilt.

Chait: Right. Although, you know, you’ve lost all your talent, you’ve lost your institutional memory, and then you’re probably rebuilding this agency from scratch.

And keep in mind, USAID is just the test case. I think they’re just picking on the most politically vulnerable agency. It deals with foreign aid, right? So most of the people affected by this right now are mostly living in other countries, who won’t get, you know, drinking water and food. And people are going to starve and die of diseases, but they’re not going to be Americans. They can’t vote, so they’re politically weak and vulnerable.

So that’s the target that they’ve picked to establish this principle that the presidency can pick and choose what spending is real and what isn’t. So then they’re going to start to go on to do domestic targets. But then, I think, once they’ve started attacking domestic targets, then they’re going to start dealing with political blowback in a way they’re not facing when they’re going after foreign aid.

Rosin: I see. So that’s a different political—so if that starts to happen, if we enter a period where you have people who have stake in this in the U.S., can you see any interesting alliances that could come out of that moment?

Chait: It’s really hard to see where they’re going, because Elon Musk is not proceeding from an accurate map of reality.

So to just explain what I mean by that, he said that he wants to cut—first he said—$2 trillion from the fiscal-year budget, from one year. Then he revised it down to $1 trillion. So right away, you know, when you’re just picking these random round numbers, you obviously don’t know what you’re talking about. But he said, like, basically, there’s a trillion dollars in just, you know, waste and improper payments—and there just isn’t. There’s nothing close to that by even the most expansive possible definition. So Musk thinks he’s going to just go through the budget and find waste, and just kill it and add up to a trillion dollars. And he’s obviously not.

So the question is: What happens when his fantasy starts to run into reality? Does he start to just attack social-welfare programs and end payments of food stamps and Medicaid reimbursements and programs like that to people? Does he realize that he didn’t know what he was talking about and he’s in way over his head? We don’t know how it’s going to go, but I think that is the question you’ve got to answer before you start to figure out what the politics look like.

Rosin: Right. And there’s also military budgets. Like, if you think where the giant spending is, you’re running up against budgets that will face a huge amount of resistance if you slash them in the way that he’s slashed other things.

Chait: Right. Yeah. If they start going after the Pentagon, I think you, obviously, cut pretty deeply into the Republican coalition pretty fast. I even think they’re probably starting to accumulate small amounts of domestic political targets with USAID, right? They cut off funding to a Lutheran charity, but, you know, those are midwestern religious conservatives who are operating those programs who are being targeted. Now, most of the money is going overseas, but you’re still hurting people in the United States of America. And I think that pain is going to start to spread more widely if they keep going.

Rosin: Right. Okay, so you’re describing a realistic scenario in which this whole operation does encounter resistance. There are many policy researchers—on the left, even—who have argued that the government does, in fact, need an overhaul and, more specifically, isn’t equipped for a digital age. Is there a chance that in all of this, you know, Elon Musk could usher in a more efficient, tech-friendly kind of government?

Chait: Yeah, well, that was the initial hope that some people who specialize in government reform were hoping for. Jennifer Pahlka is an expert in what’s called “state capacity,” which is just the ability of government to function and to bridge the gap between its ambitions and its actual ability to meet those ambitions.

And part of that is fixing the way government hires and fires people.

But the problem is: Elon Musk doesn’t seem to be interested in that in any way whatsoever. He’s just holed up with a bunch of engineers who don’t seem to have any expertise in government or state capacity whatsoever. And they’re just finding programs that people within this kind of right-wing bubble in which he resides think sound radical and just, you know, saying, Delete it! Delete it! and getting cheers on social media for it.

It’s just so completely haphazard. There doesn’t seem to be any interest in actually making the government, you know, operate better.

Rosin: Yeah. And I suppose Twitter did not become a better, more profitable, you know, smoother-functioning company after Elon Musk took it over. It just became a kind of tool of the culture war—like, an effective tool of the culture war.

Chait: Right. It became smaller, less profitable—jankier, but more conservative.

Rosin: Right, okay. All right. One final thing. So project far into the future. Let’s say that your blowback scenario is real. What political alliances can you see reforming? Like, if you had to predict a political realignment some years down the road that includes a reaction to everything that’s going on now, what does it look like?

Chait: Well, the Trump coalition has really been built on winning multiracial, working-class voters back from the Democrats—and those voters are disproportionately to the right on social policy—and they’ve exploited some of those progressive stances on social policy that the Democratic Party has adopted over the last decade, but they’re still relatively to the left on economics. Maybe they don’t believe in government, in the abstract, but in the specific, they really rely on programs, like nutritional aid and Medicaid, Obamacare.

And every time the Republicans have gone after those programs, their coalition has splintered. That was really a major element in killing George W. Bush during his second term. He decided to privatize social security, and that was a major cause of the decline of his popularity that made him politically toxic, along with the Iraq War and Katrina, social security privatization.

You know, you could see a version of that happening with Trump, but I wouldn’t take for granted that it’ll play out that way because we live in a different world in a lot of ways.

[Music]

Rosin: Thanks again to Jonathan Chait.

After the break: Donald Trump also has his eyes set on the FBI. We hear from The Atlantic’s Shane Harris about what that might mean.

[Break]

Rosin: Shane, welcome to the show.

Shane Harris: Hi. Thanks for having me.

Rosin: Sure. So the president asked the FBI to turn over the names of every agent who worked on the Capitol riots. What do you read into that request?

Harris: Well, I think you don’t even have to read that closely between the lines. You can just read the lines as they were sent in the order that we now have seen publicly, that went from the acting deputy attorney general, Emil Bove, of course, who had been one of Donald Trump’s lawyers as a private citizen, telling the acting director for the FBI, Look—we want the names of these people because they believe in the words that he has put, that they can no longer have trust that these FBI employees will implement the president’s agenda faithfully.

So what they are saying is that these are individuals who they don’t think are on board with Trump administration policies. And then of course, you know, we can do a little bit of inference, which is, you know, why would he go after the people who investigated January 6 and his role in it? Which was, by the way, the biggest FBI investigation in the country’s history. You know, these are the agents who interviewed and ultimately gave evidence that created the charges for the Capitol rioters—who were sent to prison, who Trump then later pardoned and who are now free—who investigated his own activity around January 6 and efforts to impede the transition from the Trump to the Biden administration.

So these are the FBI agents who did that case. And you know, what Trump is making very clear here is that, you know, he wants to identify them. He doesn’t trust them. He doesn’t trust the leadership that oversees them, and either wants them removed or moved, or we’ll see what the disciplinary action is. But some of them, he’s actually said he wants them fired immediately. He’s made pretty clear how he feels about these people and why he’s going after them, I think.

Rosin: Now, that must have landed in a very particular way at the FBI. You know the agency better than I do. As far as I understand it, I mean, you are assigned a case; you work on that case. So how have leaders in the agency responded to that request?

Harris: I think it’s been really interesting. I mean, there’s been this mixture from people I’ve talked to of: On one level, people are not surprised that Donald Trump went after FBI personnel, because it was expected that he would go after senior-leadership-level type people. I mean, he had essentially pushed out the FBI director, Christopher Wray, who—remember—became the FBI director when Donald Trump fired the previous FBI director, James Comey, in his first term.

But people were genuinely stunned by the scope of this demand to know the names of all of these agents who worked J6—and then there’s one other related case—because it’s, you know, potentially 4,000 to maybe even 6,000 personnel if you’re taking in FBI agents, analysts, people who play a support role.

But then something really fascinating has happened: There has been this—I hesitate to say the word defiant—but there are senior leaders at the FBI, including the person who is serving as the acting director right now, who essentially are saying, No, you cannot just fire agents for this reason, for no real cause. These people have protections under civil-service rules. They have due-process rights. And what’s more, some of the advocates for these folks are saying, Look—you can just read the plain language of the order that I just read to you and see that this is a retaliatory response, that what the president is doing is going after people because he doesn’t like their opinions or what they did.

As you pointed out, these thousands of agents didn’t pick to be on the case. I mean, it’s not like they raised their hand and said, Yes, please. I would like to investigate and prosecute Donald Trump. They were assigned these cases. So the leadership has actually really kind of dug in here, some of them, and essentially is saying, There’s a process for this. This isn’t fair.

Now, we’ll see how long they can resist the White House on this, but we’re seeing some real institutional pushback from the FBI, which personally, I think, is encouraging.

Rosin: I want to get more into the pushback, but I’m curious what we know about this group of agents. There’s a few thousand. Because, yes, I followed the January 6 cases. I know that it was the biggest investigation in history, but who are they? Like, if you think about losing these 4,000, is why I’m asking, what’s their expertise, and what do they generally do?

Harris: If we take that group of the J6 investigators, the agents themselves, these could be people who were pulled in from all over the country. So this could include agents that were investigating national-security-related matters, counterterrorism matters, transnational crime, narcotics. The universe of these agents, as you know, was so big because the case was so big and demanding.

Trump, though, has zeroed in, more particularly, on some individuals, including some very senior-level officials that have the title of executive assistant director, and he actually named some of these in this order. And those people were involved in things like, for instance, the Mar-a-Lago investigation, when Donald Trump took classified documents from the White House and stored them at his estate in Florida—offenses for which he was later charged under the Espionage Act.

Some of these people—one of them was the special agent in charge of the Miami Field Office, which participated in the raid on Mar-a-Lago. Others had supervisory and leadership positions on intelligence and counterintelligence matters. It was a counterintelligence squad at the Washington Field Office in D.C. that handled the Mar-a-Lago case. So, you know, he understands that there are people who, individually, separate from J6, worked on the Mar-a-Lago case, as well, and those people are being singled out too.

Rosin: Right. I mean, there are two things here. One is, we’ve talked about this in terms of other agencies, like USAID, which is: What vast institutional knowledge would you lose? So these people worked on individual cases, but also, they have a lot of expertise in counterterrorism. They just must have a large, you know, body of knowledge and experience that you could lose.

Harris: Absolutely. So let’s just take, for instance, the squad at the Washington Field Office that did the Mar-a-Lago investigation. They work in the counterintelligence division of the FBI. So when those folks are not investigating, you know, Donald Trump’s removal of classified documents, they’re looking at things like spies operating inside the United States trying to maybe steal government secrets or recruit agents in the United States. They’re looking at people who might be mishandling classified information. They look at people who might be leaking to journalists as well.

These are folks who work on highly specialized counterintelligence cases. This isn’t just something that you, you know, kind of step into, and on day one, you know how to do it. These are different kinds of tradecraft. They’re very sensitive. These people all will have high-level security clearances. They will have been vetted for these jobs. So folks who are in positions like that, when you eliminate them, you know, it’s not entirely clear to me that there is just then, like, a backup bench of people who can come in to do these really important national-security cases.

And the same would go for anyone who’s working actively on counterterrorism, you know. I mean, Donald Trump has talked a lot about his concern that there are, you know, terrorists making their way inside the United States, taking advantage of, you know, weak border security or other ways of getting into the U.S. Well, it’s FBI agents who do counterterrorism cases that investigate things like that.

So if you’re suddenly moving people with this level of expertise off their jobs, or you are creating a real disruption and distraction while they’re trying to do their jobs, I think that arguably weakens national security, it creates vulnerabilities, and it distracts the FBI from doing its job, which is to go out and not just investigate crimes but to try and stop violent crimes and bad things from happening to Americans and to the U.S. government.

Rosin: Right. So you can see the future crisis. Like, you can project a future crisis where we are vulnerable to terrorism or something like that because we’ve lost a huge amount of this expertise.

Harris: I think that’s right. Yes. It doesn’t seem to me like he is thinking through the consequences of hobbling the FBI at this moment. What he is interested in is retribution. He’s interested in payback. And he is putting, you know, not only the country, but he’s putting his administration at grave political risk by doing that.

Rosin: Okay, Shane. Here’s something else that I was wondering about. Since when did the FBI come under so much suspicion from the right? I’ve always thought of the FBI as an agency conservatives can get behind, and Trump’s attacks feel like they upend all that. It’s confusing.

Harris: Oh definitely. And this has long been one of the more baffling aspects of Donald Trump’s critique of the FBI, as he’s painting them as this kind of leftist deep state.

I mean, the FBI—I’m speaking in general terms, of course, I mean—it is a generally conservative institution, both because I think that the people who work in it are often politically conservative or just sort of dispositionally conservative. It’s a law-enforcement agency. I mean, it does everything by the book. There are jokes in the FBI about how it takes, you know, five forms that you have to fill out before you can make a move on anything. It is a very hidebound, bureaucratic, small-C conservative organization. I mean, these are cops.

Rosin: Right. Right.

Harris: Okay? It’s a bunch of cops, right? This is like, if you want to think in generalities, like, you know, USAID is like, Oh, yeah, it’s people who want to get to charities, and they worked in the Peace Corps, and they’re all about humanitarian causes. And that, too, is kind of a broad brush.

But, you know, when I talk to people who have worked in the bureau, if you knew these people, these are not people who you would associate with progressive causes. That doesn’t mean that they are sort of reactionary right-wingers. I don’t want to make that impression either. They’re very much following the rule of law. It’s a conservative institution. It is very hidebound and steeped in tradition and in regulation.

And, you know, Trump just has this image of it as this out-of-control left organization. And he has persuaded large numbers of his followers and Americans that this is true. And I have to tell you, in the 20-plus years that I’ve covered national security, one of the most fascinating and bewildering trends that I have seen is this change in political positioning, where now, people who tend to be on the left, sort of—I don’t want to say revere the FBI and the intelligence agencies but—hold them up as models of institutions of government that we need to have faith and trust in, and they’re there to try and protect people. When it was a generation ago, people on the left who were deeply skeptical of the CIA and the FBI because these agencies were involved in flagrant abuses of civil rights and of the law in the 1950s and ’60s.

And now it’s people on the right who, particularly after 9/11, used to be so reflexively defensive of the CIA and the FBI and counterterrorism and Homeland Security, who now have sort of swapped political positions with the critique on the left that see these institutions as, you know, run through with dangerous, rogue bureaucrats who want to prosecute their political enemies. I mean, it’s just like the people have switched bodies.

Rosin: Let me ask you a broader question about this. As someone who’s been tracking Trump’s attempts to rewrite the history of January 6 for a while, I could say I was a little surprised by the blanket pardon of insurrectionists, maybe a little more surprised by this effort to go after the agents who investigated them. Because—and tell me if this is an exaggeration—to me, that could send a message to supporters: If you commit violence on my behalf, not only will you not get punished, but anyone who tries to go after you will be in trouble. Which, if I continue that logic, seems like, potentially, a blank check to commit violence on the president’s behalf. Is that paranoid?

Harris: No. It’s not. It’s not. That is, I think, one of the clear risks that we face with the president behaving in the way that he has. And I would take it one step further, which is to say: The message is that if you are an FBI agent, or maybe more to the point, an FBI leader, someone in a management position, there are certain things that you should just not look into and investigate.

And not to say, like, now that the president enjoys, you know, presumptive immunity for all official acts. I mean, who knows what the FBI is even going to investigate when it comes to Donald Trump. But how good would you feel being assigned a case to look into Elon Musk or, you know, Trump campaign donors who may have engaged in illegal activity or influence peddling, the whole universe of people connected to Trump?

What he is saying by pardoning these J6 rioters is that If you are on my side, I will come protect you. And I think that will send a clear message to FBI personnel that there are whole categories of people and therefore potential criminal activity that they should not touch, because it gets into the president, his influence, his circle of friends. I think that is just a potentially ruinous development for the rule of law in the United States.

The FBI is there to investigate crimes objectively, regardless of who may have committed them. And what the president is doing now is essentially saying there’s a whole category of people who, if not outright exempt, are people that are going to fall under his protection, and for the people who might dare to investigate them, there will be consequences.

Rosin: Well, Shane, thank you, but no thank you, for laying that out in such a clear and chilling way. I appreciate it.

Harris: My pleasure, Hanna. Thanks for having me.

[Music]

Rosin: This episode of Radio Atlantic was produced by Jinae West. It was edited by Claudine Ebeid and engineered by Rob Smierciak. Claudine Ebeid is the executive producer of Atlantic audio, and Andrea Valdez is our managing editor.

I’m Hanna Rosin. Thank you for listening.

A politically powerful opponent of birthright citizenship railed that the United States cannot “give up the right” to “expel” dangerous “trespassers” who “invade [our] borders,” “wander in gangs,” and “infest society.”

Was this Donald Trump speaking in 2024? No, the quote is from an 1866 speech on the Senate floor by Senator Edgar Cowan of Pennsylvania, a leading opponent of adding a provision to the U.S. Constitution granting citizenship based solely on birth on U.S. soil. Who were the “invaders” that Senator Cowan so feared? “I mean the Gypsies,” Cowan explained, despite offering no evidence that Roma migration posed a risk to the United States.

Senator Cowan lost the fight. In 1868, the nation ratified the Fourteenth Amendment, the first sentence of which guarantees birthright citizenship. The amendment invalidated the Supreme Court’s infamous 1857 decision in Dred Scott v. Sandford, which declared that no Black person could ever be a U.S. citizen. Equally important, the Constitution now guaranteed citizenship to the children of immigrants born on U.S. soil, “no matter from what quarter of the globe he or his ancestors may have come,” as one senator later put it in a speech to his constituents.

[Martha S. Jones: Birthright citizenship was won by freed slaves]

More than 150 years later, Trump has vowed to end birthright citizenship on “day one” of his new administration for children without at least one parent who is a citizen or green-card holder. He made that announcement in a three-minute video prominently posted on his campaign website, which he repeated in an interview with NBC’s Meet the Press last month.

In 2025, the end of birthright citizenship is more than just an applause line at the Conservative Political Action Conference. It has a genuine, if slim, chance of making its way into law. If it does, it will upend the lives of millions, and create a caste system in which a new set of people—native-born non-Americans—can never work or live in the open.

This prospect ought to be taken seriously. How would President Trump implement such a plan? Is it constitutional? And would the U.S. Supreme Court back him up?

The first question is easy, because Trump has told us exactly how he intends to proceed. In the video, the president-elect commits to issuing an executive order on January 20, 2025, that would deny citizenship not only to the children of undocumented immigrants but also to those born to parents who both are legally in the United States on a temporary visa for study or work. (Trump’s order as proposed would apply only to children born after it is issued.)

The consequences would be immediate. Trump says he will order government officials to deny these children passports and Social Security numbers. They will be prohibited from enrolling in federal programs such as Medicaid, the Children’s Health Insurance Program, and the Supplemental Nutrition Assistance Program, and likely state benefits as well.

As adults, if all goes according to Trump’s plan, they will be barred from voting, holding elected office, and serving on juries. States could deny them a driver’s license and block them from attending state universities. They would be prohibited from working in the United States, and any U.S. citizen who employs them could be fined or even jailed under federal immigration laws. Many would be rendered stateless. Perhaps worst of all, they would live in perpetual fear of being deported from the only country in which they have ever lived.

[Read: Trump’s murky plan to end birthright citizenship]

Ending birthright citizenship for these children would affect everyone in America. Everyone would now have to provide proof of their parents’ citizenship or immigration status on the date of their birth to qualify for the rights and benefits of citizenship. The new law would necessitate an expanded government bureaucracy to scrutinize hospital records, birth certificates, naturalization oaths, and green-card applications.

Lawsuits are sure to follow, which leads to the second question: Will Trump have the constitutional authority to end birthright citizenship for the children of undocumented immigrants?

Per the text of the Constitution, the answer is a hard no. Some constitutional provisions are fuzzy, but the citizenship clause is not one of them. It states: “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”

Even the deeply racist Supreme Court back in 1898 couldn’t find any wiggle room in that language. Just two years before, in 1896, the Court had somehow read the Constitution’s equal-protection clause to permit “separate but equal” in Plessy v. Ferguson, ushering in the Jim Crow era. But when the U.S. government argued in United States v. Wong Kim Ark that the children of Chinese immigrants were not birthright citizens, the justices balked. The language granting citizenship to “all persons born” in the United States was “universal,” the Court explained, restricted “only by place and jurisdiction.” More recently, the Supreme Court reaffirmed that point, stating as an aside in a 1982 opinion addressing the rights of undocumented children to attend school: “No plausible distinction with respect to Fourteenth Amendment ‘jurisdiction’ can be drawn between resident aliens whose entry into the United States was lawful, and resident aliens whose entry was unlawful.”

Despite the clear text and long-standing judicial precedent, Trump claims that undocumented immigrants and their children are not “subject to the jurisdiction” of the United States, and so fall within the exception to universal birthright citizenship.

That is nonsense. Undocumented immigrants must follow all federal and state laws. When they violate criminal laws, they are jailed. If they park illegally, they are ticketed. They are required to pay their taxes and renew their driver’s license, just like everyone else. Trump certainly agrees that undocumented parents of native-born children can be deported for violating immigration laws at any time. So in what way are these immigrants and their children not subject to U.S. jurisdiction?

The citizenship clause’s exception for those not “subject to the jurisdiction” of the United States applies only to children born to members of American Indian tribes and the children of diplomats, as Congress explained when drafting that language in 1866. In contrast with undocumented immigrants, both groups owe allegiance to a separate sovereign, and both are immune from certain state and federal laws. (Native Americans were granted birthright citizenship by federal statute in 1924.)

As nonsensical as they are in an American context, Trump’s ideas didn’t come out of nowhere. In 1985, the law professor Peter Schuck and the political scientist Rogers Smith wrote an influential book, Citizenship Without Consent, arguing that the Fourteenth Amendment’s citizenship clause did not apply to the children of undocumented immigrants. These scholars asserted that “immigration to the United States was entirely unregulated” before the 1870s, and so there was no such thing as an “illegal immigrant” and likewise no intent to grant birthright citizenship to their children. Many scholars and commentators, including some members of Congress, have repeated that same claim. In 2015, the law professor Lino Graglia testified before the House Judiciary Committee that “there were no illegal aliens in 1868 because there were no restrictions on immigration.” Then-Representative Raúl Labrador repeated the same point at that hearing, asserting as fact that there was “no illegal immigration when the Fourteenth Amendment came into being.” In an op-ed in June 2023, a former Department of Homeland Security policy adviser declared, “There were no immigrant parents living unlawfully in the United States” in the 19th century.

These critics have their facts wrong. In a recent law-review article, the legal scholars Gabriel Chin and Paul Finkelman explained that for decades, Africans were illegally brought to the United States as slaves even after Congress outlawed the international slave trade in 1808, making them the “illegal aliens” of their day. The nation was well aware of that problem. Government efforts to shut down the slave trade and deport illegally imported enslaved people were widely reported throughout the years leading up to the Civil War. Yet no one credible, then or now, would argue that the children of those slaves were to be excluded from the citizenship clause—a constitutional provision intended to overrule Dred Scott v. Sandford by giving U.S. citizenship to the 4.5 million Black people then living in the United States.

[Read: Birthright citizenship wasn’t born in America]

Even so, these ideas have gained traction in the right-wing legal community—a group that will be empowered in Trump’s next term. The Fifth Circuit judge James C. Ho, who is regularly floated as a potential nominee to the Supreme Court, recently said in an interview that children of “invading aliens” are not citizens, because “birthright citizenship obviously doesn’t apply in case of war or invasion”—a reversal of his previous position on this issue. (This is the judicial equivalent of shouting, “Pick me! Pick me!”) Never mind that undocumented immigrants—a majority of whom entered the United States legally and then overstayed their visa—don’t qualify as invaders under any definition of the word. And never mind that there is no support for that idea in either the Constitution’s text or its history. In 1866, Senator Cowan opposed granting citizenship to the children of the “flood” of Chinese immigrants into California, as well as to Gypsy “invaders” of his own state. His colleagues pointed out that the only invasion of Pennsylvania was by Confederate soldiers a few years before. Birthright citizenship, they explained, would ensure that the United States would never revert back to the slave society that the Confederates invaded Pennsylvania to preserve.

In truth, all of these baseless arguments are window dressing for the real goal. The Fourteenth Amendment’s overarching purpose was to end a caste system in which some people had more rights under the law than others. To be sure, that ideal has always been a work in progress. But many opponents of birthright citizenship don’t even hold out that ideal as a goal; they would rather bring caste back, and enshrine it in our laws.

If birthright citizenship were to end tomorrow for children without at least one parent who was a citizen or lawful permanent resident, it would bar from citizenship hundreds of thousands of people each year. These people wouldn’t be eligible to participate in our democracy, and they would be forced to live and work in the shadows, as would their children and their children’s children. The end of birthright citizenship would create a caste of millions of un-Americans, locked in perpetuity into an inferior, exploitable status. Ironically, if Trump were to succeed in ending birthright citizenship, he would preside over the most dramatic increase of undocumented immigrants in U.S. history.

That brings us to the third question: Would five members of the Supreme Court uphold Trump’s proposed executive order?

No sitting justice has addressed this question directly. At his confirmation hearing in 2006, Justice Samuel Alito was asked whether he thought the children of undocumented immigrants qualified for birthright citizenship under the Fourteenth Amendment. He refused to answer on the grounds that a future case might come before him, but he also observed: “It may turn out to be a very simple question. It may turn out to be a complicated question. Without studying the question, I don’t know.” Justice Amy Coney Barrett declined to respond to the same question for the same reason. (These two justices also dodged questions about whether they would overturn Roe v. Wade on those grounds.)  

The Georgetown law professor Steve Vladeck, an expert on the Supreme Court, believes that, at most, “two” or “maybe … even three justices” on the current Court would vote to end birthright citizenship. But all it takes is five, and the Court’s composition may well change. Trump appointed three justices during his first term in office, and he could appoint a few more before the end of his second. It is they who will have the last word.

A slab of uplifted rock larger than Italy sits in the center of the American Southwest. It is called the Colorado Plateau, and it is a beautiful place, higher ground in every sense. What little rain falls onto the plateau has helped to inscribe spectacular canyons into its surface. Ice Age mammoth hunters were likely the first human beings to wander among its layered cliff faces and mesas, where the exposed sedimentary rock comes in every color between peach and vermillion. Native Americans liked what they saw, or so it seems: The plateau has been inhabited ever since, usually by many tribes. They buried their dead in its soil and built homes that blend in with the landscape. In the very heart of the plateau, the Ancestral Pueblo people wedged brick dwellings directly into the banded cliffs.

Some of the best-preserved Ancestral Pueblo ruins are located near two 9,000-foot buttes in southeastern Utah, 75 miles from where its borders form a pair of crosshairs with those of Colorado, New Mexico, and Arizona. The Ancestral Pueblo were not the only Native Americans in the area. Other tribes lived nearby, or often passed through, and many of them describe the buttes as “Bears Ears” in their own languages. Thousands of archaeological sites are scattered across the area, but they have not always been properly cared for. Uranium miners laid siege to the landscape during the early atomic age, and in the decades since, many dwellings and graves have been looted.

In 2015, five federally recognized tribes—the Navajo Nation, the Zuni, the Hopi, the Mountain Ute, and the Ute—joined together to request that President Barack Obama make Bears Ears a national monument. The Bears Ears Inter-Tribal Coalition, as they called themselves, wanted to protect as many cultural sites as possible from further desecration. They asked for nearly 2 million acres centered on the buttes. In 2016, Obama created a monument of roughly two-thirds that size.

The borders of that monument have been shifting ever since. In late 2017, President Donald Trump erased all but roughly 15 percent of the protected land, in the name of reversing federal overreach and restoring local control; and in the years that followed, mining companies staked more than 80 new hard-rock claims within its former borders. The majority were for uranium and vanadium, minerals that are in demand again, now that a new nuclear arms race is on, and tech companies are looking for fresh ways to power the AI revolution.

In 2021, President Joe Biden put the monument’s borders back to where they’d started—and the miners’ claims were put on hold. Now Trump is reportedly planning to shrink Bears Ears once again, possibly during his first week in office.

With every new election, more than 1 million acres have flickered in and out of federal protection. People on both sides of the fight over Bears Ears feel jerked around. In southeastern Utah, the whipsaw of American politics is playing out on the ground, frustrating everyone, and with no end in sight.

Vaughn Hadenfeldt has worked as a backcountry guide in Bears Ears since the 1970s. He specializes in archaeological expeditions. Back when he started, the area was besieged by smash-and-grab looters. They used backhoes to dig up thousand-year-old graves in broad daylight, he told me. Some of these graves are known to contain ceramics covered in geometrical patterns, turquoise jewelry, and macaw-feather sashes sourced from the tropics. Thieves made off with goods like these without even bothering to refill the holes. Later on, after Bears Ears had become a popular Utah stopover for tourists passing through to Monument Valley, the looters had to be more discreet. They started coming in the winter months, Hadenfeldt told me, and refilling the ancient graves that they pillaged. “The majority of the people follow the rules, but it takes so few people who don’t to create lifelong impacts on this type of landscape,” he said.

Hadenfeldt lives in Bluff, Utah, a small town to the southeast of Bears Ears. Its population of 260 includes members of the Navajo Nation, artists, writers, archaeologists, and people who make their living in the gentler outdoor recreation activities. (Think backpacking and rock climbing, not ATVs.) The town’s mayor, Ann Leppanen, told me that, on the whole, her constituents strongly oppose any attempt to shrink the monument. More tourists are coming, and now they aren’t just passing through on the way to Monument Valley. They’re spending a night or two, enjoying oat-milk lattes and the like before heading off to Bears Ears.

[Read: What kinds of monuments does Trump value?]

But Bluff is a blue pinprick in bright-red southern Utah, where this one town’s affection for the monument is not so widely shared. Bayley Hedglin, the mayor of Monticello, a larger town some 50 miles north, described Bluff to me as a second-home community, a place for “people from outside the area”—code for Californians—or retirees. For her and her constituents, the monument and other public lands that surround Monticello are like a boa constrictor, suffocating their town by forcing it into a tourism economy of low-paying, seasonal jobs. The extra hikers who have descended on the area often need rescuing. She said they strain local emergency-services budgets.

I asked Hedglin which industries she would prefer. “Extraction,” she said. Her father and grandfather were both uranium miners. “San Juan County was built on mining, and at one time, we were very wealthy,” she said. She understood that the monument was created at the behest of a marginalized community, but pointed out that the residents of Monticello, where the median household income is less than $64,000, are marginalized in their own right. I asked what percentage of them support the national monument. “You could probably find 10,” she said. “10 percent?” I asked. “No, 10 people,” she replied.

The two bluffs known as the "Bears Ears" stand off in the distance at sunset in the Bears Ears National Monument on May 11, 2017 outside Blanding, Utah. George Frey / Getty

The election-to-election uncertainty is itself a burden, Hedglin said. “It makes it hard to plan for the future. Even if Trump shrinks the monument again, we can’t make the development plans that we need in Monticello, because we know that there will be another election coming.” Britt Hornsby, a staunchly pro-monument city-council member in Bluff, seemed just as disheartened by what he called the federal government’s “ping-pong approach” to Bears Ears. “We’ve had some folks in town looking to start a guiding business,” he said, “but they have been unable to get special recreation permits with all the back-and-forth.”

[Read: Return the national parks to the tribes]

The only conventional uranium-processing mill still active in the United States sits just outside the borders of another nearby town, Blanding. Phil Lyman, who, until recently, represented Blanding and much of the surrounding area in Utah’s House of Representatives, has lived there all of his life. Lyman personifies resistance to the monument. He told me that archaeological sites were never looted en masse, as Hadenfeldt had said. This account of the landscape was simply “a lie.” (In 2009, federal agents raided homes in Blanding and elsewhere, recovering some 40,000 potentially stolen artifacts.) While Lyman was serving as the local county commissioner in 2014, two years before Bears Ears was created, he led an illegal ATV ride into a canyon that the Bureau of Land Management had closed in order to protect Ancestral Pueblo cliff dwellings. Some associates of the anti-government militant Ammon Bundy rode along with him. A few were armed.

To avoid violence, assembled federal agents did not make immediate arrests, but Lyman was later convicted, and served 10 days in jail. The stunt earned him a pardon from Trump and a more prominent political profile in Utah.When Biden re-expanded the monument in 2021, Lyman was furious. While he offered general support for the state of Utah’s legal efforts to reverse Biden’s order, he also said that his paramount concern was not these “lesser legal arguments” but “the federal occupation of Utah” itself. Like many people in rural Utah, Lyman sees the monument as yet another government land grab, in a state where more than 60 percent of the land is public. The feds had colluded with environmentalists to designate the monument to shut down industries, in a manner befitting of Communists, he told me.

Davina Smith, who sits on the board of the Bears Ears Inter-Tribal Coalition as representative for the Navajo Nation, grew up just a mile outside of Bears Ears. She now lives in Blanding, not far from Lyman. Her father, like Mayor Hedglin’s, was a uranium miner. But Native Americans haven’t always been treated like they belong here, she told me. “People in Utah say that they want local control, but when we tried to deal with the state, we were not viewed as locals.” Indeed, for more than 30 years, San Juan County’s government was specifically designed to keep input from the Navajo to a minimum. Only in 2017 did a federal court strike down a racial-gerrymandering scheme that had kept Navajo voting power confined to one district.

Smith, too, has been tormented by what she called the “never-ending cycle of uncertainty” over the monument. The tribes have just spent three years negotiating a new land-management plan with the Biden administration, and it may be all for naught. “Each new administration comes in with different plans and shifting priorities, and nothing ever feels like it’s moving toward a permanent solution,” Smith said.

The judicial branch of the federal government will have some decisions of its own to make about the monument, and may inject still more reversals. In 2017, the Bears Ears Inter-Tribal Coalition and other groups sued the government over Trump’s original downsizing order, arguing that the president’s power to create national monuments under the Antiquities Act is a ratchet—a power to create, not shrink or destroy. No federal judge had ruled on that legal question by the time of Biden’s re-expansion, and the lawsuit was stayed. If Trump now shrinks the monument again, the lawsuit will likely be reactivated, and new ones likely filed. A subsequent ruling in Trump’s favor would have far-reaching implications if it were upheld by the Supreme Court. It would defang the Antiquities Act, a statute that was written to protect Native American heritage, empowering any president to shrink any of America’s national monuments on a whim. (The Biden administration launched an historic run of monument creation. Project 2025, a policy blueprint co-written by Trump’s former head of BLM, calls for a shrinking spree.) The borders of each one could begin to pulsate with every subsequent presidential handover.

An act of Congress might be the only way to permanently resolve the Bears Ears issue. Even with Republican lawmakers in control, such an outcome may be preferable to the endless flip-flops of executive power, Hillary Hoffmann, a co-director of the Bears Ears Inter-Tribal Coalition, told me. “The tribes have built bipartisan relationships with members of Congress.” They might not get as much land for the monument as they did under Obama or Biden, she said, but perhaps a grand bargain could be struck. A smaller allotment of protected land could be exchanged for the stability that would allow local communities—including monument supporters and opponents alike—to plan for their future.

In the meantime, people in southeastern Utah are waiting to see what Trump actually does. When I asked Smith how the tribes are preparing for the new administration, she was coy. She didn’t want to telegraph the coalition’s next moves. “We are definitely planning,” she told me. “This isn’t our first time.” Everyone in the fight over Bears Ears has to find some way to cope with the uncertainty; for Smith, it’s taking the long view. She invoked the deeper history of the Colorado Plateau. She called back to the Long Walk of the Navajo, a series of 53 forced marches that the U.S. Army used to remove thousands of tribe members from their land in New Mexico and Arizona in the 1860s. “When the cavalry came to round up my people, some of them sought refuge in Bears Ears,” she said. “To this day, I can go there and remember what my ancestors did. I can remember that we come from a great line of resilience.”