The Kremlin, eager to make the choice harder, has leaned heavily into the narrative that the president is risking escalation. Last week, it ran a series of exercises over how to move and use its large arsenal of tactical nuclear weapons.
After Mr. Stoltenberg’s statement to The Economist, the Kremlin’s top spokesman, Dmitry Peskov, said that “NATO is flirting with military rhetoric and falling into military ecstasy,” and that the Russian military knew how to respond. Asked if the Western alliance was nearing a direct confrontation with Russia, he said: “They are not getting close; they are in it.”
American officials are increasingly dismissing such warnings as empty. Russia, they note, has never taken the risk of attacking the supply of weapons to Ukraine in Poland or elsewhere in NATO territory. President Vladimir V. Putin has done everything he could to avoid direct conflict with the Western alliance, even while showing off his nuclear capabilities or warning, as Mr. Peskov does regularly, that the West was risking turning a regional conflict into World War III.
“Putin is rattling the nuclear saber to keep Biden from letting U.S. weapons be used to counterattack,” Joseph S. Nye, a former American military official and leader of the National Intelligence Council, said on Tuesday. Mr. Nye, an emeritus professor at Harvard, noted that “what you have happening is a nuclear bargaining game, and a credibility game.”
“Putin has higher stakes in this one, and he will push hard to make Biden swerve first,” he added.
That has been true since the first days of the war, when Mr. Putin ordered nuclear forces to be placed on alert, in an effort to keep NATO from helping Ukraine after the invasion. But after repeated threats from Mr. Putin that he might make use of nuclear weapons, Mr. Biden’s aides seem less and less impressed by the Russian president’s declarations.