President Vladimir V. Putin has threatened to reach into Russia’s arsenal of nuclear weapons at three points in time in the past two years: once at the outset of the war against Ukraine two years ago, once when he was losing ground and again on Thursday, as he senses that he is grinding down Ukrainian defenses and American resolve.

In each instance, the saber rattling has served the same basic purpose. Mr. Putin knows that his opponents — led by President Biden — fear escalation of the conflict most of all. Even bluster about going nuclear serves as a reminder to Mr. Putin’s many adversaries of the risks of pushing him too far.

But Mr. Putin’s equivalent of a State of the Union speech on Thursday also contained some distinct new elements. He not only signaled that he was doubling down on his “special military operation” in Ukraine. He also made clear that he had no intention of renegotiating the last major arms-control treaty in force with the United States — one that runs out in less than two years — unless the new deal decides Ukraine’s fate, presumably with much of it in Russia’s hands.

Some would call it nuclear chess, others nuclear blackmail. Implicit in Mr. Putin’s insistence that nuclear controls and the continued existence of the Ukrainian state must be decided together is the threat that the Russian leader would be happy to see all the current limits on deployed strategic weapons expire. That would free him to deploy as many nuclear weapons as he wants.

And while Mr. Putin said he had no interest in pursuing another arms race, which helped bankrupt the Soviet Union, the implication was that the United States and Russia, already in a constant state of confrontation, would return to the worst competition of the Cold War.

“We are dealing with a state,” he said, referring to the United States, “whose ruling circles are taking openly hostile actions against us. So what?”