The president’s grim assessment, delivered during a Democratic fundraiser on Thursday night, rippled around the world and appeared to edge beyond the boundaries of current U.S. intelligence assessments.
U.S. security officials continue to say they have no evidence that Vladimir Putin has imminent plans for a nuclear strike.
Biden spoke about Ukraine at the end of his standard fundraising remarks, saying that Putin was “not joking when he talks about the use of tactical nuclear weapons or biological or chemical weapons.”
“We have not faced the prospect of Armageddon since Kennedy and the Cuban Missile Crisis,” he added. He suggested the threat from Putin is real “because his military is — you might say — significantly underperforming.”
White House press secretary Karine Jean-Pierre on Friday did not directly respond to a question about whether Biden had gone into the event intending to invoke Armageddon, as the White House sought to clarify the president's comments.
She told reporters: “Russia’s talk of using nuclear weapons is irresponsible and there’s no way to use them without unintended consequences. It cannot happen.” She added that "if the Cuban Missile Crisis has taught us anything, it is the value of reducing nuclear risk and not brandishing it.”
She reiterated that the U.S. has “not seen any reason to adjust our own strategic nuclear posture nor do we have indications that Russia is preparing to imminently use nuclear weapons.”
For months, Biden’s national security team has warned that Russia could use weapons of mass destruction in Ukraine as it faces strategic setbacks on the battlefield. But the president's remarks were the starkest warnings yet by the U.S. government about the nuclear stakes.
One U.S. official said Biden was also trying to warn against underestimating the danger of any level of tactical nuclear weapons.
There is some concern in the Biden administration that Russia has determined it can use its nuclear arsenal in a manner short of a “full-blown” nuclear attack on Ukraine and face only limited reaction from U.S. and Western allies who want to avoid a broadened war, according to the official who spoke on condition of anonymity.
Putin has repeatedly alluded to using his country’s vast nuclear arsenal, including last month when he announced plans to conscript Russian men to serve in Ukraine.
“I want to remind you that our country also has various means of destruction ... and when the territorial integrity of our country is threatened, to protect Russia and our people, we will certainly use all the means at our disposal,” Putin said. “It’s not a bluff.”
In Europe, leaders sought to turn down the volume after Biden’s stark warning.
Asked about Biden’s remarks, French President Emmanuel Macron said it was crucial to speak with care on the nuclear threat.
“I have always refused to engage in political fiction, and especially ... when speaking of nuclear weapons,” Macron said at a EU summit in Prague. “On this issue, we must be very careful.”
European Council President Charles Michel told reporters “we are going to remain calm" and "keep cool heads" regarding Russia's threats.
“Overseas countries are saying, ‘Whoa, this is what the U.S. president says,” said Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, and a veteran of nuclear policy research. “And so that means we have to be really careful about using big words” that in themselves can escalate nuclear tensions unintentionally.