Will Putin go nuclear? A timeline of expert comments

“No matter who tries to stand in our way or all the more so create threats for our country and our people, they must know that Russia will respond immediately, and the consequences will be such as you have never seen in your entire history,” President Vladimir Putin said in a statement widely interpreted as a nuclear threat.

“No,” President Biden said in response to a question about whether US citizens should be concerned about the start of a nuclear war.

"At this time, we see no reason to change our own [nuclear] alert levels," White House press secretary Jen Psaki said.

"I think it's very unlikely that Moscow is just going to lob a nuclear weapon at something," Olga Oliker with the International Crisis Group said. "Obviously it's been a week when a lot of people's assumptions have been challenged, but I'll cling to this one for a while."

“It seems unimaginable that Russia would use nuclear weapons in Ukraine,” Lynn Rusten, a former White House staffer now at the Nuclear Threat Initiative, said. “There would be no reason for it.” 

“There is always the danger of inadvertent escalation,” Pavel Podvig, senior researcher at the UN Institute for Disarmament Research, said.

“The prospect of nuclear conflict, once unthinkable, is now back within the realm of possibility,” UN Secretary General António Guterres said.

“From a risk perspective, I believe we could be at about five or 10 percent of the Cuban Missile Crisis risk level,” Herb Lin, a security scholar at Stanford and the Hoover Instititution, said. 

“As this war and its consequences slowly weaken Russian conventional strength, Russia likely will increasingly rely on its nuclear deterrent to signal the West and project strength to its internal and external audiences,” Lt. Gen. Scott Berrier, director of the Defense Intelligence Agency, wrote in a report.

“I think we have to start from the presumption that he would welcome the opportunity to use nuclear weapons," Gen. (Ret.) Wesley Clark said. "He wants to show his determination. He wants to intimidate the West. He thinks he has a nuclear advantage.”

"The Russians have told us that they have made no changes thus far in the operational status of their missiles per se, and I don't have any reason not to believe that,” Rose Gottemoeller, former deputy secretary general of NATO and undersecretary for arms control in the Obama administration, said.

“The chances [of Russia using a nuclear weapon] are low but rising,” said Ulrich Kühn, a nuclear expert at the University of Hamburg and the Carnegie Endowment for International Peace told the New York Times. “The war is not going well for the Russians, and the pressure from the West is increasing.”

“[The probability that war in Ukraine will devolve into nuclear war is] less than one in 100—and in my best estimate, closer to one in 1,000,” Harvard political scientist Graham Allison said.

“The risks of a direct confrontation between US and Russian forces may be fairly low at present,” Michael Dobbs, author of One Minute to Midnight, an account of the Cuban missile crisis, said. “But if you multiply that by X months or X years and the number of things that could go wrong, they turn out to be similar mathematically [to the one-in-three nuclear-war odds that President John F. Kennedy had calculated during the Cuban Missile Crisis].”

“[Potential nuclear weapon use in the current war] is something we do have to be concerned about,” US National Security Adviser Jake Sullivan said.

“We have a special document on nuclear deterrence. This document clearly indicates the grounds on which the Russian Federation is entitled to use nuclear weapons. … [This includes] when an act of aggression is committed against Russia and its allies, which jeopardized the existence of the country itself, even without the use of nuclear weapons, that is, with the use of conventional weapons,” Dmitry Medvedev, former Russian president and deputy chairman of the country’s security council, said.

“The likelihood of Putin actually using nuclear weapons remains low, but the threat is still there,” Shannon Bugos, a senior policy analyst at the Arms Control Association, said.

“No one is thinking about using, about—even about idea of using a nuclear weapon, Kremlin Spokesman Dmitry Peskov said.

“… Russia could introduce nuclear weapons into a conflict when it felt it had run out of conventional options and was facing an existential threat,” Sarah Bidgood, director of the Eurasia program at James Martin Center for Nonproliferation Studies, said. “It’s hard to say, because we don’t have a good sense for what all of Putin’s red lines are here, or what he regards as an existential threat.”

“No indications at this time that they’re preparing to use [nuclear] weapons,” a senior US defense official, speaking on the condition of anonymity, said.  

“None of that’s evident,” Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, said of Russia preparing for nuclear war.

“Russia firmly adheres to the principle that there can be no winners in a nuclear war, and it must not be unleashed," Russia's First Deputy Permanent Representative to the United Nations Dmitry Polyanskiy said.

“The risk of Russia using a nuclear weapon in Ukraine is very low, and the public concern over nuclear use has far outstripped the nuclear risk,” Adam Mount, director of the Defense Posture Project at the Federation of American Scientists, said. “In some ways, it’s the threat that’s meant to do more work than the weapon itself.”

“I think the odds of him using chemical or nuclear weapons is at this point pretty low,” Former US Secretary of Defense Robert Gates said.

“[G]iven the potential desperation of President Putin and the Russian leadership, given the setbacks that they’ve faced so far militarily, none of us can take lightly the threat posed by a potential resort to tactical nuclear weapons or low-yield nuclear weapons,” CIA Director William Burns said. “While we’ve seen some rhetorical posturing on the part of the Kremlin, about moving to higher nuclear alert levels, so far we haven’t seen a lot of practical evidence of the kind of deployments or military dispositions that would reinforce that concern.”

“We shouldn’t wait for the moment when Russia decides to use nuclear weapons​.​ … We must prepare for that​,” Ukrainian President Volodymyr Zelensky said.

“Putin could order the Russian military to drop a single nuclear bomb on a Ukrainian city to try to coerce the Zelensky government into immediately surrendering. This frightening scenario is not fanciful. It is, after all, effectively what the United States did to Japan in 1945,” Scott Sagan, senior fellow at Stanford’s Spogli Institute for International Studies, said.

“[The new Sarmat intercontinental ballistic missile capable of carrying nuclear warheads] will force all who are trying to threaten our country in the heat of frenzied, aggressive rhetoric to think twice,” President Vladimir Putin said.

“I don’t really know [whether Putin is going to use nuclear weapons in Ukraine], although the chances are certainly non-zero,” Siegfried Hecker, former director of Los Alamos National Laboratory and one of the world’s foremost security experts, said.

“When nuclear deterrence fails, it fails catastrophically,” Daryl Kimball, director of the Arms Control Association in Washington, DC, said.