Analysts and pundits in the United States and Europe are increasingly optimistic that Ukraine can win its war against Russia. They also are prodding the Biden administration to increase the flow of military hardware to Kyiv to maximize Ukraine’s chances of victory. A new missive along those lines comes from Council on Foreign Relations Senior Fellow Max Boot in a May 2 Washington Post column. Boot contends that the United States should provide Ukraine “with every weapon it needs to win.” Nor, according to Boot, should the administration let Vladimir Putin’s threats of escalation deter Washington from that course of action.

More worrisome than recklessly hawkish sentiments from smug pundits is that U.S. and European officials also speak openly of helping Ukraine win its war and inflict a humiliating defeat on Russia. The U.S. delegation headed by House Speaker Nancy Pelosi that visited Kyiv at the beginning of May repeatedly emphasized that theme, along with a pledge of Washington’s continuing military assistance until victory is achieved.

What such individuals do not seem to comprehend is that Ukraine is a vital Russian security interest, and the Kremlin likely will do whatever is necessary—probably even the use of tactical nuclear weapons—to prevent a defeat. The failure to understand just how important Ukraine is to Russia caused Western leaders to disregard Moscow’s warnings over more than a decade against making Kyiv a NATO member or an informal military ally. For the same reason, they seem to be making an even more dangerous blunder by ignoring the Kremlin’s latest warnings about dire consequences if NATO uses Ukraine as a pawn in a proxy war against Russia.

Boot and other pundits even dismiss comments coming from Russia about the possible use of tactical nuclear weapons. Michael McFaul, a former U.S. ambassador to Russia, contends blithely that warnings from Putin about using nuclear weapons in response to mounting Western military assistance to Kyiv should be ignored. “The threat of escalation is cheap talk,” McFaul states confidently. “Putin is bluffing.”

Boot likewise considers the risk of a nuclear confrontation to be minimal. “The least likely scenario is the most apocalyptic one: Russia attacking NATO countries with conventional or nuclear weapons. Putin isn’t suicidal, and he knows that the U.S. response would be devastating.” Boot does concede that “a more limited use of nuclear weapons against Ukrainian bases or population centers is slightly more plausible.” However, Biden can thwart such a scenario

…by emphasizing that, while under current circumstances the United States will not fight Russia directly, all bets are off if Putin goes nuclear. Even without resorting to nuclear weapons of their own, NATO could launch airstrikes that would rapidly sink the entire Russian Black Sea fleet and destroy much of the Russian army in and around Ukraine. That would shake Putin’s criminal regime to its foundations.

Such confident hawks insist that the Biden administration not give in to Russia’s “nuclear blackmail.” They seem serenely oblivious to the probable consequences if they are wrong. Typically, Boot appears to believe that the mere threat of NATO airstrikes against Russian targets would intimidate Putin. The possibility that Russia would instead decide to wage a wider nuclear war in response to sinking “the entire Russian Black Sea fleet” or the destruction of “much of the Russian army in and around Ukraine” doesn’t seem even to occur to him. Yet such a response from a cornered great power facing a catastrophic defeat involving a vital security interest (a compliant Ukraine) is not only possible, it is highly probable.

Contrary to the dangerously blasé attitudes on the part of foreign policy hawks, it is imperative for the United States and its NATO allies to take the Kremlin’s new warnings very seriously. Perhaps Western elites erroneously believe that Russian leaders are as prone as their U.S. counterparts to invoke the concept of vital interests with casual promiscuity. Political leaders who insisted that Vietnam and Iraq constituted vital U.S. security interests were certainly guilty of that offense. The degree of risk that the United States is incurring to assist Ukraine is the latest evidence of such carelessness and sloppy thinking.

However, nations have genuine vital interests, and great powers will do almost anything to prevail in such situations. For example, the United States would never tolerate outside interference if it took military action to prevent Canada or Mexico from joining a powerful, hostile military alliance led by China. Any effort on Beijing’s part to support a Canadian or Mexican armed “resistance” would be considered an extremely provocative act. And if Washington concluded that because of that outside interference it was about to lose the war, it would be extraordinarily hazardous for the People’s Republic of China to assume that U.S. leaders would keep the conflict non-nuclear.

Ukraine occupies an importance to Russia comparable to Canada’s or Mexico’s importance to the United States. Preventing Ukraine from becoming a NATO military pawn is the most vital of vital interests to Russian leaders. The closer that Moscow comes to suffering defeat in the Ukraine war, the more likely it is that the Kremlin will do whatever is necessary, take whatever risks are necessary, to prevent such an outcome. Advocates of helping Ukraine achieve “victory” and thereby humiliate Russia are flirting with Armageddon.