The Russian Federation has begun to look a bit like the Titanic. Impressively presented and expensively made, Vladimir Putin’s revived Russian military enjoyed an outsize reputation. Nervous neighbors imagined Moscow launching a modern blitzkrieg, conquering much of Europe and establishing a new Russian Empire.

Then came Putin’s February invasion of Ukraine. Seven months after an attack that was supposed to seize Kiev and oust the Zelensky government in days, the campaign is moving in reverse, with a dramatic counteroffensive from Ukraine. Even as Putin headlined a gaudy Kremlin event celebrating the annexation of four Ukrainian oblasts, Ukraine’s military was liberating more territory supposedly under Moscow’s control. Putin looked ridiculous rather than fearsome and his government’s “partial mobilization” appeared to show the regime’s desperation, not determination.

The Russian state is still capable of doing enormous harm. By one estimate, Moscow can continue the war for another two or three years without suffering budget distress. And Russia’s nuclear stockpile gives substance to Putin’s not so veiled threats to use nukes. Exactly for what purpose and in what way is not so clear. Most obviously, Moscow desires to keep NATO, meaning the U.S., out of the war. Russia relies on nuclear weapons to help make up for its conventional inferiority. Reminding Washington of that fact might help dissuade the Biden administration from directly coming to Ukraine’s defense.

Moscow also could use nuclear weapons to gain advantage against Kiev directly. Dmitry Medvedev, top Putin ally and presidential stand-in, suggested using nukes against “the Ukrainian regime” whose aggression “is dangerous for the very existence of our state.” Most officials suggest defensive use, pointing to any Ukrainian attempt to retake Crimea or the newly annexed territories.

More ominously, an embattled Russia could deploy nuclear weapons in an attempt to force Ukraine’s surrender. In that case, Moscow might target Ukrainian cities with strategic weapons. The purpose would be to terrorize and kill, in hopes of forcing Ukraine’s surrender.

The effort would be ruinous, even mad, leaving little to rule. And the blowback would be intense. The West would be fully estranged, at least so long as Putin or his allies were in control. Even Moscow’s supposed friends, most importantly China and India, could not easily tolerate mass murder. The U.S. would be under strong pressure to respond militarily, strengthening its nuclear shield for Europe and even striking Russian forces in Ukraine.

More likely, Moscow would use tactical nuclear weapons to make battlefield gains, whether offensive or defensive—with the additional hope of intimidating Kiev to make peace on Russia’s terms. Moscow already has powerful conventional weapons available for use but could hope tactical nukes would “escalate to deescalate,” convincing the allies that the cost of intervention is too high and too risky. Being only the second state to use nuclear weapons, and the only one to do so in the last 77 years, would leave Russia even more isolated internationally and NATO considering retaliatory options.

Surely the U.S. and its European allies should consider their response if Moscow uses nuclear weapons, whether strategic or tactical. There aren’t a lot of new sanctions to apply, especially against the Russian state. NATO members, mostly meaning the U.S., could upgrade the weapons being sent to Ukraine, but Moscow might further escalate. Other ideas also would entail substantial risk, such as “a decapitation strike to kill Putin in the heart of the Kremlin.” Failure would guarantee Russian retaliation.

Equally important, Washington should consult with leading states that have been reluctant to sanction Russia for its invasion. Their unwillingness so far to sacrifice their interests on behalf of allied geopolitical objectives should surprise no one. The threat by Moscow to trigger a nuclear conflagration could change their calculus, however, convincing them to lean against the Putin government. Still, even criticism from India and China is likely to have only limited impact if Russia otherwise believes use of nuclear weapons to be necessary.

For good reason the West would like to dissuade Moscow from taking this route. But how? U.S. and allied threats are of little value. To its credit, the Biden administration has approached the issue with caution, warning Moscow against loosing nukes, threatening “catastrophic” and “horrific” consequences and a “consequential” and decisive response, but without promising war. Nuclear weapons should make the U.S. and other governments cautious, especially in a case like this.

First, U.S. attempts at deterrence are likely to fail. One intelligence officer asked journalist William Arkin: “Threatening to respond forcefully and creating catastrophic consequences for Russia [without] suggesting nuclear war: Is that strong enough to deter Putin?” Probably not. But then, a tougher approach threatening nuclear war also isn’t likely to deter him. After all, is it credible to imagine that the U.S. is prepared to risk nuclear war and destruction of its homeland to prevent Russia from using nuclear weapons against a nation the U.S. has refused to sacrifice any lives to defend?

Second, Russia’s attack on Ukraine, though a vicious crime, is not America’s war. There is good reason for the U.S. to punish the Russian government and aid Ukraine in its defense, but Washington’s interest in the struggle is modest. The welfare of the American people remains foremost. It is easy to sit in Washington and discuss what Moscow should do. That is irrelevant to what the Russian government will do. Ukraine is an existential issue for Moscow, which means Russia will incur more costs and take more risks than will Washington.

Third, relations between the U.S. and Russian Federation already are fraught after years of confrontation and sanctions. Simultaneously fighting a proxy war against Washington and a very hot one against Kiev has added incendiaries to the bilateral relationship. National security aide Fiona Hill contends that the U.S. already is fighting World War III. If that is how she feels, imagine how Moscow likely views the bilateral relationship.