Why the world is worried about Russia’s ‘tactical’ nuclear weapons

“In the face of a threat to the territorial integrity of our country, to protect Russia and our people, we will certainly use all the means at our disposal,” Putin said. He and top officials have since echoed the sentiment.

For several months, the United States has been sending private communications to Moscow warning Russia’s leadership of the grave consequences that would follow the use of a nuclear weapon, according to U.S. officials. President Biden warned this week that the risk of nuclear “Armageddon” is higher than at any time since the Cuban missile crisis.

The strategic landscape has been complicated by the roughly 1,500 “tactical” warheads Russia has stockpiled since the Cold War ended. These smaller nuclear weapons, which are far less powerful than the ones the United States dropped on the Japanese cities of Hiroshima and Nagasaki during World War II, are designed to be used on the battlefield.

The smaller size of the weapons, some experts fear, could break down the nuclear taboo. They warn against underestimating what are still weapons of mass destruction, with the potential to cause widespread casualties from radiation alone.

Sarah Bidgood, director of the Eurasia program at the James Martin Center for Nonproliferation Studies in Monterey, Calif., said it was hard to estimate the level of risk that Russia would use a tactical nuke in Ukraine, but that it was clear that Russia relied on its nuclear weapons, including tactical weapons, to give it flexibility in managing the risk of escalation.

“Russia could introduce nuclear weapons into a conflict when it felt it had run out of conventional options and was facing an existential threat,” she said. But, she added, “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.”