“I think that really stems from his personal worldview. Where do you go [on the nuclear issue]? You go to Russia.”

In a wide-ranging speech Wednesday before a crowd of 6,000 at the Brandenburg Gate in Berlin, Obama said that after “a comprehensive review,” he has concluded that the United States can cut its deployed strategic nuclear weapons by one-third while still ensuring the nation’s safety.

“And I intend to seek negotiated cuts with Russia to move beyond Cold War nuclear postures,” Obama told the crowd.

Disputes over human rights and the civil war in Syria have rattled US-Russian relations over the past year, but a push by the Obama administration for cooperation on nuclear nonproliferation overlaps with its “intention to improve and keep the bilateral relationship at a working, respectful level,” Kupchan said.

“What I think the administration is intent on doing is to ensure a functional and mutually beneficial relationship with Russia on key issues,” said Kupchan, a former US State Department official. “There is no naivete' that Russia will be like the UK.”

Obama’s proposal Wednesday did not come as a surprise, nonproliferation experts said. He had been expected to announce a further drive for reductions at some point – the only question was how far the proposed cuts would go, analyst Steven Pifer told RIA Novosti.

“I think what you saw in that statement today was first and foremost about the president trying to take further steps to find a nuclear legacy to leave behind,” said Pifer, a former US ambassador to Ukraine and director of the arms control initiative at the Brookings Institution.

In his most recent State of the Union address in February, Obama said that he planned to engage Moscow in an attempt to further slash its nuclear arsenals. The New York Times reported days before that speech that his administration wanted to negotiate an informal agreement with the Kremlin to reduce each country’s strategic nuclear arsenal to between 1,000 and 1,100 deployed warheads.

Those cuts would be even deeper than the 1,550 deployed warheads allowed by the New Strategic Arms Reduction Treaty (START) that Obama and former Russian President Dmitry Medvedev signed in 2010.

The negotiations that led to that pact were a logical forum for cooperation after Obama took office in 2009, a time when the bilateral relationship was “either totally dysfunctional or non-operative,” said Andrew Weiss, a former Russia expert in the National Security Council under President Bill Clinton.

“We knew how to do things in the arms-control realm even during the worst days of tension between Washington and Moscow during the Cold War,” Weiss, vice president for studies with the Carnegie Endowment in Washington, told RIA Novosti.

The New START treaty, however, came at time when the previous strategic arms reduction treaty was set to expire, giving both sides an impetus to hammer out a deal, Weiss said. Further cuts of the kind proposed by Obama on Wednesday are lacking such an “action-forcing event,” meaning Washington could face significant obstacles in convincing Russia that such cuts are necessary, he added.

Obama’s desire to leave a lasting legacy on nuclear nonproliferation “may not be a persuasive argument in Moscow, where there’s been a clear connection drawn between offense and defense, and where going back decades there are longstanding Russian concerns about US missile defense development directly impacting Russia’s willingness to cut strategic forces,” Weiss said.

Russian Deputy Prime Minister Dmitry Rogozin aired such concerns immediately after Obama’s announcement Wednesday, saying Moscow could not “take seriously” such proposals while Washington pursues a missile defense system vehemently opposed by the Kremlin.

“How can we take seriously this idea about cuts in strategic nuclear potential while the United States is developing its capabilities to intercept Russia's nuclear potential,” Rogozin told reporters in St. Petersburg.