Former Vice President Joseph R. Biden Jr., the Democratic nominee, was involved in the negotiation of the original 2010 agreement and has indicated that, if elected, he would agree to a straightforward, five-year extension and work later to expand its scope.
Leonid Slutsky, head of the Russian Legislature’s international affairs committee, said Mr. Putin’s proposal would remove pressure for a deal before the accord expires and disentangle arms talks from pre-election politics in the United States.
The Trump administration has balked at agreeing to a five-year extension without revisions, an option provided for in the original treaty and one that would not require Senate approval. Mr. Trump has deemed that unacceptable because the treaty signed by President Obama did not cover all of Russia’s nuclear arms, or any of China’s.
China, however, has refused to join any revised version of New Start, arguing that its nuclear arsenal is tiny compared with those of the United States or Russia.
While eager to salvage New Start, Russia has shown little interest in giving President Trump a foreign policy victory ahead of a United States presidential election now less than three weeks away, indicating, perhaps, that it expects Mr. Biden to win. Senior Russian officials this week poured scorn on claims on Tuesday by Mr. Trump’s lead negotiator, Marshall Billingslea, of an “agreement in principle, at the highest levels of our two governments, to extend the treaty.”
Russia’s deputy foreign minister, Sergei A. Ryabkov, dismissed this as fantasy. “Washington is describing what is desired, not what is real,” Mr. Ryabkov, Russia’s chief negotiator, said in a statement.
Russia’s open mockery of the supposed deal, however, left Moscow looking churlish and risked compromising Mr. Putin’s longstanding efforts to present his country as deeply committed to arms control — in contrast to the United States, which has walked away from a number of accords in the past.