By HELENE COOPER

WASHINGTON - When he has focused on Russia at all, Barack Obama’s attention has been concentrated primarily on the need to keep Soviet nuclear weapons out of the hands of terrorists.
But now, President Dmitri A. Medvedev of Russia has thrown down a gauntlet to the American presidentelect. The day after the election, as leaders around the world were lining up to congratulate Mr. Obama, Mr. Medvedev delivered a harsh welcome- to-the-new-cold-war speech in Moscow.
He said he would deploy shortrange missiles near Poland capable of striking NATO territory if the United States pressed ahead with plans to build a missile defense shield in Europe, something Mr. Obama has said he supports. He put Mr. Obama on notice on the Georgia crisis as well, vowing that “we shall not retreat in the Caucasus.”
“It was a giant, ‘Hey, welcome to the game,’ ” said George Friedman, chief executive at Stratfor, a geopolitical risk analysis company. “While Obama would like to deal sequentially with Iraq, Afghanistan and, when he gets to it, the Russians, the Russians themselves want to be a burning issue at the top of his list.”
Mr. Obama, for his part, has yet to respond to the Russian aggressiveness, and he probably will not do so until after his inauguration in January, his advisers said.
“We only have one president at a time,” Mr. Obama said during a news conference, responding to a question about whether he would soon meet with foes of the United States. “I want to make sure that we are sending the world one message.”
Since the election, the Obama team has taken pains not to say anything that could signal Mr. Obama’s thinking on major foreign policy issues.
The reasons are twofold. Many of those advisers are privately hoping for positions in his administration, and they do not want to jeopardize their chances by talking freely. More significantly, Mr. Obama himself is still making the transition from campaign oratory - and very strong campaign oratory, in Russia’s case - to the more nuanced approach that many advisers say will be necessary to navigate contentious relationships.
But some of his comments during the campaign may already have limited his options. When Russia invaded Georgia in August, his initial response was balanced, urging both nations to exercise restraint. However, under pressure from his opponent, Senator John McCain, who responded with a hard-line approach, Mr. Obama toughened his position. He accused Russia of encroaching on Georgia’s sovereignty, asserted that Russia bore responsibility for the escalation and even voiced support for Georgia’s entry into NATO, a position that Russia had practically dared the West to take.
Mr. Obama has options to distance himself from his hawkish remarks on Russia, foreign policy experts said. For one thing, while he can continue to support the idea of Georgia becoming part of NATO, the reality is that for now the Europeans will not go along.
Beyond that, Mr. Obama could try to strike more benign agreements that Russians might find soothing, like pushing again for Russia’s entry into the World Trade Organization and working with Moscow toward a way out of the missile defense morass. One possibility would be to offer to delay deployment of a missile shield in Poland until an Iranian nuclear threat - which Washington says is its reason for being - has actually materialized, instead of doing so immediately.
The Bush administration might even lend a hand; it has made several proposals to Moscow, including an offer to let Russian military officials inspect the missile defense installations planned in Poland and the Czech Republic.
What Mr. Obama will not be able to do, foreign policy specialists said, is cede the former Soviet republics and satellites in Eastern Europe back into the orbit of what the Russians like to call their near abroad.
It is a full docket of issues, and a long way from Mr. Obama’s first engagement with Russia policy, when he joined the Senate Foreign Relations Committee on a tour of Russia, Ukraine and Azerbaijan in 2005 with Senator Richard Lugar of Indiana, the Republican elder statesman on foreign policy. Later, as the senators described their trip, Mr. Obama often deferred to Mr. Lugar, according to people who attended the session. It was clear, they said, who was the old foreign policy hand and who was the junior senator.