WASHINGTON - President Obama plans to open negotiations on Wednesday to draft a new arms control treaty that could slash the American and Russian strategic nuclear arsenals by about a third and possibly lead to even deeper reductions, according to administration officials.
As Mr. Obama arrived in London on Tuesday for his first European trip as president, American and Russian officials have privately indicated that they could agree to reducing their stockpiles perhaps to about 1,500 warheads apiece, down from the 2,200 allowed under a treaty signed by President George W. Bush.
The two sides plan to draft the treaty quickly so it can be signed in time to replace the Strategic Arms Reduction Treaty, or Start, which expires in December after 15 years as the broadest legal foundation of Russian-American nuclear policy. Washington and Moscow hope quick success replacing a pact negotiated in the waning days of the cold war will help revive a strained relationship and set the stage for further arms cuts.
"Just setting a new limit would send a signal to the international community in general that the United States was getting serious about its disarmament commitments again," said Peter Crail, an analyst at the Arms Control Association, a Washington advocacy organization.
Mr. Obama is to meet President Dmitri A. Medvedev for the first time on Wednesday in London on the sidelines of the Group of 20 economic summit meeting, and they plan to announce the beginning of the talks to replace Start. Obama administration officials also said they expected the two to advance cooperation on other thorny issues, including Afghanistan and Iran.
Mr. Medvedev, in an Op-Ed article published Tuesday in The Washington Post, said he was already seeing better relations since Mr. Obama's inauguration.
"Neither Russia nor the United States can tolerate drift and indifference in our relations," Mr. Medvedev wrote. He placed blame for the rift on Mr. Bush's efforts to build a missile defense system and enlarge NATO in Moscow's former sphere of influence, making no mention of Russia's war with Georgia last year.
"Possible areas of cooperation abound," Mr. Medvedev said. "For instance, I agree with President Obama that resuming the disarmament process should become our immediate priority. The wish to ensure absolute security in a unilateral way is a dangerous illusion. I am encouraged that our new partners in Washington realize this."
American and Russian officials decided to tackle arms control in part because it seemed the least contentious of their issues. The Russians like talking about arms control because it is one area where they remain relatively on a par with the United States. Mr. Bush scorned arms control as the basis of relations, seeing it as anachronistic, and the treaty he signed was so general it came to fewer than 500 words.
Mr. Obama, by contrast, promised during the campaign to restart traditional arms control talks and take "steps down the long road toward eliminating nuclear weapons."
"The Obama administration and the president see arms control as an important tool to advance American security," said Steven Pifer, a former deputy assistant secretary of state under Mr. Bush. "That's a big philosophical difference."
Mr. Pifer, now at the Brookings Institution, said Mr. Obama's initiative could finally bury the cold-war nuclear legacy. "It's cleaning up some unfinished business that's been put on hold for the last seven years," he said.
Of course, opening meetings between American and Russian leaders often begin with hope, only to deteriorate later. In June 2001, when Mr. Bush first met with Vladimir V. Putin, then Russia's president and now its prime minister, Mr. Bush famously said that "I looked the man in the eye" and "I was able to get a sense of his soul."
But their cordial relationship degenerated into crisis by last year's war in Georgia.
The treaty that expires on Dec. 5, Start I, was signed in 1991 before the collapse of the Soviet Union and went into effect in 1994, requiring both sides to reduce their arsenals to 6,000 warheads. Start II was never fully ratified, and a framework for a Start III never went anywhere.
The Strategic Offensive Reductions Treaty, signed by Mr. Bush in 2002, cut arsenals to the range of 1,700 to 2,200 by 2012, relying on the verification program set up by Start. But it allowed warheads to be stored rather than destroyed, and, unlike Start, it imposed no restrictions on delivery vehicles, like intercontinental ballistic missiles, heavy bombers or nuclear-armed submarines.
The process Mr. Obama and Mr. Medvedev begin Wednesday will essentially be a two-stage effort. Because Start I expires soon and Washington's latest nuclear policy review is still under way, the first stage will focus on getting a replacement to preserve the inspection and verification system established under Start I, combined with a reduction to perhaps 1,500 warheads.
Then next year, the two sides envision a more ambitious agreement that could reduce warheads further, even to 1,000, as well as limit delivery vehicles and possibly tactical nuclear weapons. Start limited each side to 1,600 delivery vehicles but both have already cut below that. Mr. Pifer said a new treaty could bring each down to 600 or 700.
As they focus first on the Start replacement, the two sides appear relatively close on the overall ceiling, but they face other tough issues, most significantly the counting rules. American officials have signaled flexibility but insist that adopting rules that Moscow wants will require more transparency and intrusive inspections, according to people briefed on the unofficial, preliminary discussions.
Another potential complication is the planned American missile defense system in Eastern Europe to defend against a possible Iranian threat. Russian representatives told the Americans that with a 1,500-warhead ceiling, there might be no need to settle the missile defense issue to reach an initial treaty deal. If they want to go lower, to 1,200 or 1,000 warheads, then, the Russians said, they would insist on constraints on missile defense.
The Americans want to avoid having missile defense thrown into the mix, warning that it would make it hard to get a treaty done in time. At a confirmation hearing last Thursday, Rose Gottemoeller, nominated to serve as the assistant secretary of state for verification and compliance and the chief negotiator for the treaty, testified that she wanted to avoid extra issues.
"In my view, we will keep the agenda tight," she said. "We will keep it focused."
Senator Richard G. Lugar, an Indiana Republican, said the treaty would have to be signed by August for the Senate to ratify it by Dec. 5. If it cannot be done by then, the Obama administration has talked about possibly signing the pact before the deadline and extending Start until the replacement can be ratified.