Why Putin suspended New START after Biden's Kyiv trip

What did it mean when Russia's President Vladimir Putin suspended his country's participation in the New START treaty on 21 February 2023? The treaty was the last remaining nuclear arms control pact with the United States, and the suspension came one day after a visit to Kyiv that had been kept secret until it happened.

The justification

Putin cited the U.S. goal of defeating Russia in the war in Ukraine as his reason. The argument tied the fate of a nuclear arms agreement directly to the battlefield, linking two issues that had previously been handled on separate tracks.

The Kyiv visit

On 20 February 2023, U.S. President Joe Biden made an unannounced visit to Kyiv, where he met Ukraine's President Volodymyr Zelenskyy. Out of security concerns, his travel plans had not been made public beforehand. As reported at the time, only two journalists accompanied him, and they had been sworn to secrecy three days earlier.

What the sequence shows

The two events came on consecutive days, and both were framed around the war. Washington's president appeared in the Ukrainian capital in person. Moscow's president then announced the suspension of its participation in the only remaining treaty constraining the nuclear arsenals of the two countries.

The suspension was Russia's choice, and it was justified by Putin in terms of the war. For Ukraine's partners, the episode showed that the conflict was now bound up with questions of strategic stability between Russia and the United States. The treaty was a mechanism for arms control between the two powers; with Russia's participation suspended, that mechanism no longer had a functioning Russian side.

For international readers, the lesson of 21 February 2023 is that the war's consequences were no longer confined to Ukraine's territory. A visit to Kyiv and a decision in Moscow, a day apart, placed the war alongside the question of nuclear arms control.