When President Biden made a blunt warning at a fundraiser last Thursday that the war in Ukraine could turn into a nuclear “armageddon”, it raised a terrifying prospect that many Americans hadn’t cared much about since the end of the Cold War.
White House officials did not retract Biden’s statement; they knew it reflected a deep concern that has led the Pentagon and intelligence officials to look at different scenarios, from a test detonation over the Black Sea to the use of a nuclear weapon against, say, a Ukrainian military base. But the White House stressed Friday that the United States has seen no signs that Russia is preparing to use nuclear weapons.
But it’s been 30 years since most Americans talked about nuclear deterrence, the difference between tactical and strategic weapons, and what havoc a 10-kiloton versus a 100-kiloton bomb can wreak. So what was the president talking about?
This is what we know:
As his military loses ground, Putin has been waving his nuclear saber.
President Vladimir V. Putin of Russia, in an angry speech last month, full of bluster and anti-American rhetoric, clearly raised the specter of using nuclear weapons to hold on to its territorial gains in Ukraine.
Putin said he would use “all available means” to defend Russian territory, which he stated includes four provinces in eastern Ukraine that Russia has attempted to illegally annex. He also argued that the atomic bombs the United States dropped on Japan in 1945 “created a precedent.”
Mr. Biden, last Thursday, said: “For the first time since the Cuban Missile Crisis, we have a direct threat to the use of nuclear weapons, if indeed things continue the way they are.”
So far, US officials say they believe the chances of Russia using nuclear weapons are low.
Senior US officials say they have seen no evidence that Putin is moving any of his nuclear assets, especially in Russia’s stockpile of some 2,000 tactical small arms.
Although Mr. Putin called for its nuclear forces to be put on alert as of late February, there has been no evidence that they did. But events like the attack on the Kerch Strait bridge over the weekend worry officials who fear a humiliated Putin is more likely to lash out.
Still, US officials have been weighing possible scenarios.
Senior US officials are far more concerned than at the start of the conflict about the possibility of Putin deploying tactical nuclear weapons.
After a series of humiliating retirements, staggeringly high casualty rates, and a deeply unpopular move to conscript young Russians into service, Putin clearly sees the threat of his nuclear arsenal as a way to instill fear and perhaps regain some respect for the power of Russia. .
For months, computer simulations by the Pentagon, US nuclear labs and intelligence agencies have been trying to model what might happen and how the US might respond.
The threshold at which Putin would resort to nuclear weapons, or how he would use them, is far from clear. The main use of a tactical nuclear strike, many US officials say, would be as part of a last-ditch effort by Putin to stop Ukraine’s counteroffensive by threatening to make parts of the country uninhabitable.
Russia will most likely deploy tactical nuclear weapons, which have smaller payloads than intercontinental ballistic missiles.
Analysts say that if Putin resorts to nuclear weapons, the most likely scenario would be a relatively small tactical strike, either on the battlefield or as a warning shot in an unpopulated area.
Tactical weapons come in many sizes and varieties, some with a small fraction of the destructive power of the bombs the United States dropped on Hiroshima and Nagasaki in 1945, and others with much greater power. They can be fired from an artillery cannon or launched from a missile.
But they are difficult to use and they are difficult to control. The amount of destruction, and lingering radiation, depends on factors including the size of the weapon and the winds. Even a small nuclear explosion could kill thousands and render a base or city center uninhabitable for years.
The risks to Putin could easily outweigh any profit: Depending on natural winds, radiation released by Russian weapons could easily return to Russian territory.
The West has been vague about how it would respond.
Mr. Biden recently said that the United States would “respond forcefully” if Mr. Putin uses a tactical nuclear weapon. In May wrote in an essay for The Times that “any use of nuclear weapons in this conflict on any scale” “would carry serious consequences.” His national security adviser, Jake Sullivan, said on September 25 that there would be “catastrophic consequences” and those had been communicated to Moscow.
But that doesn’t necessarily mean a retaliatory nuclear strike, which could trigger a broader war. For months, administration officials have said that they can hardly think of any circumstances in which a Russian nuclear detonation in Ukraine would result in a US nuclear response.
There have been discussions of various other military responses, such as using conventional weapons against a base or unit from which the attack originated, or providing Ukrainian forces with the weaponry to launch that counterattack.
But many of the options under discussion also involve non-military measures, such as further isolating Russia from the world economy and portraying Putin as an international pariah. It would be an opportunity, some officials say, to bring China and India, along with much of Asia and Africa, into the effort to impose sanctions on Russia, taking away some of the biggest remaining markets for its oil and gas.