In the centuries-long war between humans and cockroaches, the most bitter blow was dealt roughly 40 years ago. Tired of chasing after the pests with noxious sprays and bombs, researchers started to infuse their poisons with delicious flavors that could compel roaches to approach of their own accord, and then feast upon their own demise. The secret was sugar: Cockroaches, like us, simply couldn’t resist their sweet tooth.

The advent of these baits “revolutionized pest control,” says Coby Schal, an entomologist at North Carolina State University. Manufacturers were sure that they had, after centuries of strife, gained a decisive upper hand. And victory was sweet.

But not even a decade passed before the battlefield shifted once again. In the late 1980s, the manufacturers of Combat, a popular roach bait, received a perplexed call from a pest-control operator in Florida. He’d been planting Combat all over homes for years, but suddenly, it was failing to seduce German cockroaches to their deaths. One of the company’s researchers, Jules Silverman, plucked several roaches from a Gainesville apartment—and was flabbergasted to find that the insects were no longer tempted by Combat’s corn syrup and instead scuttled away in disgust.

Silverman had stumbled upon an evolutionary accident. Lured irresistibly to sugar-laced poisons for years, most of the roaches in the apartment had died. But a few insects, born with an unusual set of genetic changes that rewired their sense of taste, were no longer attracted to the baits—and, unlike their sugar-addicted kin, lived long enough to pass their mutations on to their offspring. Populations of bait-snubbing cockroaches have since been discovered in other parts of the world, even as far away as Russia, each of them apparently evolving their aversion independently, Schal told me. Faced with saccharine death, roaches adapted at warp speed, turning a liability on its head—yet another reason why they remain some of our most persistent pests.

[Read: Why you can’t keep cockroaches out of your home]

Cockroaches’ aversion to sweetness came with costs. Meats, nuts, and super-complex starchy foods, such as beans, still taste mostly fine. But anything that contains a pure infusion of the simple sugar glucose, or that rapidly breaks down into it, registers to the mutant cockroaches as horrifically bitter, says Ayako Wada-Katsumata, an entomologist at North Carolina State University. That’s likely a problem for bugs in the sugar-addicted Western world, Schal said, because they “eat whatever we eat”—candy, pastries, and packaged snacks galore. “Imagine an infestation in a Dunkin’ Donuts,” Schal told me. Starved of low-carb options, the mutant roaches might struggle to eat enough. Wada-Katsumata and Schal haven’t done much work in doughnut shops. But their experiments in the lab do show that when baits are scarce and sugary foods flow free, the mutant cockroaches get rapidly outcompeted by their glucose-loving cousins.

The Atkins-esque diet has taken a toll on German cockroaches’ sex lives too. Prior to Sugargate, the insects had a standard courtship protocol: Males extruded a fatty, sugary “nuptial gift” from a gland on their back to tempt prospective mates into a tryst. Chemically speaking, the secretion is “similar to chocolate,” with comparable allure, Wada-Katsumata told me. If tasty enough, the nuptial gift could coax lady roaches into sitting down for an extended snack—five, six, seven seconds, perhaps longer—enough time for her suitor to initiate an hour-plus-long mating embrace, at the end of which he would deliver a package of sperm.

But the male’s precoital treat holds no appeal for sugar-loathing females. It’s chock-full of maltose, a type of sugar the female’s saliva rapidly converts to glucose. “So at first she is interested,” Wada-Katsumata told me. Within a couple of seconds, though, the taste turns foul—prompting her to skedaddle, her eggs still unfertilized. Weeks may pass before the female is ready to couple anew, if she ever becomes interested in trying again. “She learns that the courtship process is not good because of the bitter taste,” Wada-Katsumata said.

[Read: This cyborg cockroach could save your life someday]

This sounds, in theory, like “it should have been great for humans,” says Justa Heinen-Kay, an evolutionary biologist at the University of Minnesota. And perhaps at first it was, as cockroaches were forced to navigate a “tug-of-war” between poison-survival and sex, says Jessica Ware, an entomologist at the American Museum of Natural History. Sugar-loving roaches were doomed to die in traps, while their keto-dieting kin perished without spawning another generation of pests.

And yet, of course: Faced with this conundrum, cockroaches have tinkered with an evolutionary work-around. By studying lab-reared populations of German cockroaches, Wada-Katsumata and Schal have found that sugar-averse females seem to be producing saliva that’s less effective at converting maltose to glucose, making the taste of nuptial gifts less noxious—while still helping them steer clear of glucose-rich baits. Males have conjured up at least two adaptations to match. They’re tweaking the composition of their gift to contain less maltose in favor of a more complex sugar that’s tougher for roach saliva to break down. And they seem to be engaging the female faster after she begins to feed—as if steeling themselves against the possibility that “she’ll get grossed out and leave,” Heinen-Kay told me.

All of that adds up, once again, to a losing stance for humans. Many of our tasty baits are turning obsolete—and the insects appear to be reproducing just fine. “It reminds us how quickly pests can adapt,” Ware told me, especially under immense pressure from us. This certainly isn’t the first time that our meddling has caused other animals to evolve rapidly over centuries or even just decades: Stripped of tree cover amid rampant deforestation, some of New Zealand’s stone flies jettisoned their ability to fly; under pressure from ivory poachers, elephants in Mozambique have begun to birth tuskless calves.

[Read: African elephants evolved tusklessness amazingly fast]

But the feats of German cockroaches are particularly notable for their speed and breadth, says Chow-Yang Lee, an urban entomologist at UC Riverside. And although other animals may eventually collide with the limits of their adaptive flexibility, cockroaches—already infamous for their ubiquity and near indestructibility—seem to be just warming up. That’s probably part of the reason these roaches are everywhere: on every continent save for Antarctica, ubiquitously plaguing us in and around our homes.

Trap manufacturers haven’t yet given up on concocting baits to accommodate the insects’ new dietary quirks—fattier, saltier, or more savory ones may be available soon. But it may only be a matter of time before the roaches find the loopholes in those new lures too. Lee, who’s been studying the insects for decades, doesn’t dare underestimate their pluck. Among their kin, German cockroaches “are probably the most resilient of all,” he told me. “They overcome challenges over and over. You cannot help but have a lot of respect.”

Russia’s unprovoked, unjustified invasion of Ukraine last year and, for that matter, its first invasion of its neighbor eight years before are impossible to justify. Putin is trying to convince his public that this war is existential, but with little success. Russia’s existence as a strong, sovereign state is not dependent on its control of Ukraine or even parts of the Donbas or Crimea. That’s why since Russian President Vladimir Putin implemented a partial mobilization last fall, hundreds of thousands of men have fled Russia rather than march to the sound of the guns, and it’s why he still refuses to declare war and order a full mobilization.

And yet a small band of critics has rallied beneath the banner of realism to argue against continued Western support for Ukraine’s effort to defend itself. “Russia may be waging a war of aggression as a matter of law,” Mario Loyola wrote in a recent essay in The Atlantic, “but as a matter of history and strategy it is moving to forestall a grave deterioration in its strategic position, with stakes that are almost as existential for it as they are for Ukraine.” But actual realism must be grounded in the details of the situations it assesses. And in the case of Ukraine, those facts lead to very different conclusions.

[Mario Loyola: Ron DeSantis is right about Ukraine]

The borders of Ukraine that emerged from the breakup of the Soviet Union in 1991 were enshrined in international law and in numerous treaties and agreements that Russia signed, over and over. They were not a “formality,” as Loyola suggests, nor was Russia’s first invasion of Ukraine, and illegal annexation of Crimea, justifiable because “Russia felt it had no choice … because it couldn’t risk losing Sevastopol.” Russia shared Sevastopol with Ukraine for more than a decade and had a lease that would have lasted until the middle of the century. Ukraine was living in peace with Russia until 2014. Putin didn’t like democratic revolutions in neighboring countries, especially in Ukraine, because he feared that Russians would want the same thing, threatening his corrupt, authoritarian system. That’s why he invaded in 2014, and one of the main reasons he launched round two last year.

Loyola is not alone in suggesting that Crimea’s status be treated as a special case for Russia, that it was transferred to Ukraine “only” in 1954 and “is home to few ethnic Ukrainians even now.” Crimea is part of Ukraine. For centuries—until Stalin forcibly moved them to Central Asia during World War II—Crimean Tatars were a major presence in the peninsula even after Russia took control at the end of the 18th century, making up about 20 percent of the population at the time of the deportation (during which up to 50 percent of them died). According to the last census Ukraine administered in Crimea, in 2001, they made up about 10 percent of the population, and Ukrainians 24 percent. Their leadership has been severely repressed by the Russian occupiers. They are as much Ukrainian citizens as any others living on Ukrainian soil.

[From the December 2022 issue: The Russian empire must die]

It’s common to hear echoes of Russian propaganda that Ukraine’s pro-Russian government in Ukraine “was deposed” in 2014—but that does not make it true. Ukraine’s former President Viktor Yanukovych fled Kyiv and wound up in Russia. Another line often heard in Moscow and repeated by some in the West is that pro-Russia presidential candidates won elections until 2014. After 2004’s Orange Revolution, the pro-Western opposition leader Viktor Yushchenko beat Yanukovych in the rerun of the 2004 presidential election, despite the latter’s efforts to steal victory.

Then there is the argument that NATO enlargement was the reason behind Putin’s invasion in 2014. That, of course, overlooks the fact that Yanukovych legislatively ended Ukraine’s pursuit of closer ties with NATO—and yet Putin wasn’t satisfied with that. Had Putin not pressured Yanukovych into rejecting agreements with the European Union in 2013, the Euromaidan revolution never would have happened. And when current Ukrainian President Volodymyr Zelensky floated the idea of neutrality for Ukraine in the very early stages of Russia’s most recent invasion (before the discovery of the atrocities at Bucha and other sites), Putin wasn’t interested. Finally, Putin expressed no concerns about the Finns and Swedes applying for NATO membership.

Loyola and other realists often deny Ukraine and Ukrainians agency. Zelensky, who has performed heroically throughout the war, was democratically elected and has to take into account the views of the Ukrainian people. A recent poll by the International Republican Institute shows that 97 percent of Ukrainians think they can win the war and 74 percent believe Ukraine will maintain all territories from within its internationally recognized borders defined in 1991. Ukrainians strongly oppose any territorial concessions or compromises. They also don’t trust Russia, given how Moscow never lived up to its past commitments to Ukraine, not least the 2014 and 2015 Minsk agreements.

Moreover, Russia’s tactics—its war crimes, crimes against humanity, and genocide—have alienated Ukrainians for the foreseeable future. Putin has significantly bolstered Ukrainians’ desire to join NATO: 82 percent now say they would support joining the alliance. Invading neighbors and subjecting them to appalling abuses tends to alienate, not win over, the populations in these countries. When Loyola writes that peace “should be the overriding objective now, but it will require a willingness to compromise,” he omits that this would require forcing a deal on the Ukrainians that they vehemently oppose. It also ignores the fact that senior Russian officials, such as former President Dmitry Medvedev, and the Russian media have said that a key objective of the invasion is to destroy “Ukrainianness,” which is why some observers accuse Moscow of committing not just war crimes but genocide.

The presence of Russian occupiers in Ukrainian territory is unacceptable to Ukrainians. Not only would a peace deal ceding territory betray Ukraine and the concepts of sovereignty and territorial integrity, but it would also justify Putin’s view that the West is weak, and that he can accept its gift of part of Ukraine now—effectively a reward for aggression—and then come back for more, in Ukraine and farther West. China’s President Xi Jinping is also watching the West’s response, and drawing lessons about what the international community might do were he to attack Taiwan.

[Anne Applebaum: China’s war against Taiwan has already started]

Echoing other realists who tend to blame America first, Loyola implies that we pushed Ukraine into war. Nothing could be further from the truth. The Biden administration did everything it could to avert a Russian invasion, and Ukraine also tried to prevent one. Putin wanted to hear none of it, and instead made absurd demands in December 2021 that would have rolled NATO back to its pre-1997 borders and entrenched Russian control over the Eurasian region. What’s more, despite the dreadful performance of his military, Putin has yet to jettison his original, maximalist war aims.

The costs of letting Putin have his way in Ukraine, including the damage it would cause to the decades-old international order, are too grave to bear. If not stopped and defeated in Ukraine, Putin will try his luck in other countries in the region, including Moldova and possibly even the Baltic states. A Russian move against Estonia, Latvia, or Lithuania would implicate NATO’s Article 5 security guarantees, potentially pulling the United States into a war with Russia. As it is, the Baltic states have been constant targets of Kremlin provocations, including the cyberattack on Estonia in 2007; the kidnapping of an Estonian official in September 2014, shortly after a visit by President Barack Obama; and the buildup of troops in Moscow’s western military district. If Putin is able to bluff his way to victory in Ukraine, on what basis can we assume that he will not attempt the same in the Baltics? This is clearly understood in Eastern and Northern Europe, and is why traditionally neutral Sweden and Finland want to join NATO.

In Ukraine, the Ukrainians are the ones doing the fighting, and tragically the dying; the United States has no soldiers on the ground. But we have every interest in providing the military support Ukraine needs to win this war and drive every Russian occupying and invading force off Ukrainian territory. No one wants the war to end sooner than the Ukrainians, but they also believe, and with good reason, that they can win, if they get the assistance they need soon. Now is not the time to snatch Russian defeat from the Ukraine’s jaws of victory.

Russia has reignited threats against Sweden and Finland after their historic decision to try and join the Western military alliance.