Over the past several years, a medication called mifepristone has been at the center of intense moral and legal fights in the United States. The pill is the only drug approved by the FDA specifically for ending pregnancies; combined with misoprostol, it makes up the country’s most common regimen for medication abortions, which accounted for more than 60 percent of terminations in the U.S. in 2023, according to the Guttmacher Institute, a research group that supports abortion rights. And yet, mifepristone is difficult or impossible to acquire legally in about half of states. Since Roe v. Wade was overturned in 2022, multiple federal lawsuits have threatened access to the pill at the national level.

Now a preliminary study suggests that using another drug in place of mifepristone may be just as effective for terminating an early pregnancy. The drug, called ulipristal acetate and sold as a 30-milligram pill under the brand name Ella, was approved by the FDA in 2010 as prescription-only emergency contraception. In a paper published today in the journal NEJM Evidence, researchers from the reproductive-rights nonprofit Gynuity Health Projects, along with partners in Mexico, reported the results of a trial in Mexico City that included more than 100 women with pregnancies up to nine weeks’ gestation. They found that medication abortion using 60 milligrams of ulipristal acetate (the equivalent of two doses of Ella) followed by misoprostol ended 97 percent of patients’ pregnancies without any additional follow-up care. (The FDA-approved regimen of mifepristone followed by misoprostol is about 95 percent effective, but because the new study did not directly compare the ulipristal acetate–misoprostol regimen to any other, researchers can’t yet say whether it’s superior or inferior to the standard regimen of mifepristone and misoprostol or misoprostol alone.)

The new study is small and did not include a control group. But the findings raise the provocative possibility that a drug already marketed as a contraceptive could also serve, at a higher dose, as a medication for abortion—a potential substitute for mifepristone, subject to fewer restrictions, wherever the latter is banned or difficult to get. The American abortion landscape, already fragmented, just got even more complicated.

Ulipristal acetate is a chemical relative of mifepristone and the most effective emergency-contraceptive pill available in the United States. When taken within five days of unprotected sex, it delays ovulation, which in turn prevents fertilization of an egg. Studies show that Ella works better than morning-after pills containing levonorgestrel, such as Plan B One-Step, and is more effective for a longer period of time after sex. Ella may also be more effective than other morning-after pills in people with a BMI above 26, which includes most American women over the age of 20. Although Ella’s 30-milligram dose is enough to prevent pregnancy, previous studies have suggested that the amount is highly unlikely to help end pregnancy as mifepristone does, by blocking a fertilized egg from implanting in the womb or disrupting the uterine lining.

Some experts have long suspected that a higher dose of ulipristal acetate could yield a different result. But the field has been generally reluctant to pursue research on the drug as a possible abortifacient out of concern for its role as an emergency contraceptive. Studies have repeatedly shown that a lower dose of mifepristone can act as an effective emergency contraceptive when taken soon after unprotected sex, with few side effects. It’s sold that way in a handful of countries where abortion is legal and widely available—but in the U.S., it was never approved for emergency contraception, and reproductive-rights advocates have not pushed for it. “Our idea, when we developed ulipristal acetate, was precisely to get away from abortion,” says André Ulmann, the founder and former chair of HRA Pharma, the drug’s original manufacturer. He and his colleagues worried, he told me, that any association with abortion would endanger their ability to market the drug for emergency contraception.

[Read: The other abortion pill]

The new study may very well validate Ulmann’s old fears. If further research confirms its findings, Americans seeking abortions may soon have a safe and effective workaround in places where mifepristone is restricted—and American abortion opponents will have a big new target. In an NEJM Evidence editorial accompanying the Gynuity study, Daniel Grossman, a professor of obstetrics, gynecology, and reproductive sciences at UC San Francisco, argued as much, writing, “There is a risk that the findings of this study could be misapplied and used by politicians to try to restrict ulipristal for emergency contraception.” Beverly Winikoff, the president and founder of Gynuity Health Projects and a co-author of the study, told me that she knew the stakes when she and her colleagues began their research. But part of Gynuity’s mission is to safeguard abortion care. In Winikoff’s view, another potential option for medication abortion in the U.S. was too important to ignore.

In 2022, a coalition of groups that oppose abortion sued the FDA in an effort to pull mifepristone off the market. In June, the Supreme Court unanimously struck down the challenge, ruling that the anti-abortion groups lacked standing. But in October, three states filed an updated version of the same suit in federal court; last week, a federal judge ruled that the case can proceed. Currently, 14 states have a near-total ban on medication abortion, and more than a dozen others limit how the drugs can be distributed, with requirements such as an in-person visit, an ultrasound examination, and a 24-hour waiting period. More restrictions may be on the way: Project 2025, the conservative-policy plan developed by the Heritage Foundation for an incoming GOP administration, calls for the FDA to entirely withdraw the drug’s approval. President Donald Trump, however, has been inconsistent, saying that he doesn’t plan to block access to the abortion pills while simultaneously refusing to rule out the possibility.

In light of the new study, it’s hard to imagine that anti-abortion groups won’t seek similar restrictions on Ella, threatening its availability as an emergency contraceptive. Anti-abortion activists and Republican lawmakers have repeatedly sought to blur the line between abortion and contraception by reasoning that pregnancy begins not, as federal law states, after a fertilized egg has implanted in the uterus, but at the moment when egg and sperm meet. Students for Life of America claims, for example, that all forms of hormonal birth control are abortifacients. “Abortion advocates have long denied Ella’s potential to end an embryo’s life, but this study contradicts that narrative,” Donna Harrison, the director of research for the American Association of Pro-Life Obstetricians and Gynecologists—which was a plaintiff in last year’s Supreme Court case—told me in a statement. “Women deserve to be fully informed about how this drug works, as well as its risks.” (Until now, no evidence had indicated the drug’s abortifacient potential; at the dose approved for emergency contraception, there is still no evidence that Ella can disrupt an established pregnancy.)

[Read: Abortion pills have changed the post-Roe calculus]

The Gynuity study points to a possible role for ulipristal acetate as part of an abortion regimen, Kelly Cleland, the executive director of the American Society for Emergency Contraception, told me. But it doesn’t change what we know about its use for emergency contraception. For now, Ella remains on the market as just that.

Juli Gittinger keeps a bag packed with iodine pills and a machete. “It’s good for getting through brush,” she explained to me recently. Gittinger’s mind churns with images of a future in which she might have to flee her home with just a backpack, bushwhacking her way through rural Georgia to safety. She has enough water in her house to last 30 days, and enough food to last 100 days.

Gittinger, a religious-studies professor at Georgia College, is a prepper, but unlike the stereotype that term commonly conjures—a bunker-bound, right-wing conspiracist—Gittinger is liberal. She began prepping after Donald Trump was elected in 2016. Among her prepping supplies are Plan B emergency contraceptive pills that she’s bought ahead of Trump’s second inauguration, in case his administration introduces new restrictions on reproductive health care.

Gittinger is representative of a small number of preppers who oppose Trump and who are gearing up for whatever disasters the next four years might bring. Across Reddit boards and Facebook groups, they are stocking up on and freeze-drying food—and say that others should be too.

[Read: Why liberals struggle to cope with epochal change]

Precise numbers on prepping are hard to come by, but the United States has likely millions of preppers of all political persuasions, says Michael Mills, a senior lecturer at Anglia Ruskin University, in the United Kingdom. Liberals make up a small percentage—about 15 percent, according to Mills. Like their conservative counterparts, liberal preppers are worried about the stability of the economy and the power grid, but unlike the conservatives, they also worry about climate-change-induced disasters and the potential that Trump will weaken America’s security through foreign-policy snafus. Mills is skeptical that the number of liberal preppers has dramatically increased, but the moderators of several liberal-prepping forums told me they’ve seen a spike in interest and activity since Trump’s reelection, in November. Several preppers I interviewed mentioned getting current on their vaccines, in case the new administration alters the rules for vaccine insurance coverage, or updating their passports, in case they feel they have to leave the country.

In addition to being a prepper herself, Gittinger has studied prepper groups and written about them in an academic book, American Apocalyptic. Starting in 2018, Gittinger surveyed several hundred liberal preppers (and a few conservatives) on Facebook. When she asked what got them into prepping, 31 of the 300-some respondents mentioned the election of Trump, and 35 mentioned “political anxieties.” Among the calamities they feared would strike were both the politically driven—economic and societal collapse, an attack from a foreign power—and the completely random: a pandemic, a natural disaster. “The country is so divided that anything could ignite riots like we haven’t seen before,” one respondent told her.

Lots of Americans are doing some version of prepping for Trump’s second term, even if they don’t call it that. Some providers of Plan B and abortion pills say they noticed an increase in orders immediately after the election. The election prompted many to rush to buy electronics, cars, and other goods ahead of Trump’s promised tariffs. Spending on vehicles, auto parts, and appliances rose in November, The Washington Post reported. Along with stocking up on food and water in anticipation of tariffs, Gittinger recently bought a new phone, and Zoe Higgins, another liberal prepper, bought a new car.

Genevra Hsu, a moderator of the Leftist Preppers subreddit, grew up learning survivalist techniques from her father, but she began prepping in earnest around 2013, when she moved to a rural area of Virginia. Some of her friends got into gardening, and she would give them tips. She now has six months of meals on hand—she does her own pressure-canning, dehydrating, and freezing. She’s at high risk of complications from COVID, so when the pandemic started, the stores provided an “animal comfort that comes from knowing there’s enough on the shelf that I don’t have to go anywhere,” she told me. Recently, she has started dehydrating and freezing powdered eggs in case of a bird-flu pandemic. On the subreddit, preppers discuss stocking up on toothpaste with fluoride, which Trump’s chosen health secretary, Robert F. Kennedy Jr., opposes adding to tap water. They’re buying up birth control and medical textbooks for treating vaccine-preventable diseases.

[Read: What going ‘wild on health’ looks like]

The line between prepping and emergency readiness is hazy. Indeed, some of the liberal preppers I interviewed seem more worried about act-of-God disasters such as hurricanes than a Handmaid’s Tale–type dystopia. KC Davis, the author of How to Keep House While Drowning, moved to Houston after 2017’s Hurricane Harvey and became concerned about flooding and losses of power. Now she keeps canned water, headlamps, thermal blankets, life jackets, rechargeable lanterns, and 30 days of emergency food on metal racks in her garage. She also has a generator, which fired up while we were talking.

In New Orleans, Higgins has a month’s worth of freeze-dried spaghetti, beef stroganoff, chicken alfredo, and other meals. She’s procured flashlights, headlamps, waterproof matches, fire starters, water-purification tablets, camping stoves, and propane tanks, along with something she calls a “bug-out binder” containing 400 pages of emergency checklists and instructions. Some preppers admit that the gear they’ve accumulated is less a preparation for a specific, Trump-related emergency and more a consequence of prepping gradually becoming a hobby, with ever more complicated gadgets for ever more outlandish scenarios. Among Gittinger’s prep is a Faraday bag—a backpack that blocks electromagnetic signals, in which Gittinger keeps a spare phone and a computer—to be used in case of an extreme solar flare.

Over and over, liberal preppers told me that they differ from their conservative counterparts because they are less conspiracy-minded and more concerned with helping their community rather than only their immediate family. (Gittinger wouldn’t need Plan B herself, but she bought it for other young women who might.) But like their right-wing counterparts, liberal preppers do tend to own guns, according to Gittinger: 121 of the 198 people who answered her survey question about weapons said they owned a firearm. Whom, exactly, they would use them against is less clear. “I think a lot of that is just out of a response to general uncertainty,” Hsu told me.

Another major commonality between liberal and conservative preppers is a distrust of the government, a feeling that institutions won’t help you if the worst comes to pass. For liberal preppers, this feeling has grown only more pronounced since the first Trump presidency. The rise of Trump, the fall of Roe v. Wade, and Republican victories in the states have given liberals the sense that they are on the ropes. “My general feeling, especially about Texas, is that there’s not a lot of community safety-netting when it comes to emergencies,” Davis says. “It feels like sort of every man for himself.”

Her sentiment fits with what the pollster Kristen Soltis Anderson calls a “cross-partisan rise in distrust” of institutions. Republicans and Democrats now share similar levels of distrust of Congress and big business. Americans on both the left and the right feel unsupported; preppers are just doing something about it. “There’s this common thread that I think unites preppers of all political persuasions, which is a lack of faith in political progress as a whole and a skepticism towards political leadership,” Mills told me. Conservative preppers were once worried about Barack Obama, and liberals are most worried about climate disasters, but they both worry that the government doesn’t have your back.

[Jonathan Chait: How liberal America came to its senses]

Some of my conversations with liberal preppers served as good reminders to buy bottled water and flashlights in case of a natural disaster, but some of them had an air of paranoia. Many of their worst-case scenarios seemed unlikely to ever take place. What are the odds that American citizens would actually be banned from international travel? What is the likelihood that Republicans would outlaw not just Plan B, but also birth control, which is used by 82 percent of reproductive-age women?

Then again, we live in outrageous times, during which a reality-TV host can become president, for the second time, after a failed coup attempt. That president picked another TV host to be in charge of the nation’s defense. His chosen health secretary has urged parents to ignore the CDC guidelines for childhood vaccinations. Abortion is completely banned in 12 states. There really has been a global pandemic that shut down much of the world for years. There’s a sense that literally anything can happen, so you’d better be prepared.

Gittinger pointed out that when the coronavirus pandemic broke out, she had N95 masks on hand. Who’s too paranoid now?

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.