The United States is hoping new concessions over its plans to put a missile defense system in Europe will satisfy Moscow's concerns that such a move would destabilize relations between the former Cold War rivals.
But so far, Russian President Vladimir Putin doesn't appear satisfied with U.S. proposals, which include allowing Moscow to potentially station observers at the proposed defense sites.
At a European-Russian summit in Portugal last week, Putin compared the situation to the 1962 Cuban missile crisis.
"For us the situation is technologically very similar," Putin told reporters at the conference. "We have withdrawn the remains of our bases from Vietnam, from Cuba, and have liquidated everything there, while at our borders, such threats against our country are being created."
Putin, however, said his personal friendship with President Bush and the changed relationship between Moscow and Washington means the issue would not bring the two sides to the brink of war, as happened during the Cuban crisis.
Russia is not the only obstacle to U.S. plans. Skepticism in the intended host countries — Poland and the Czech Republic — is growing.
In Prague last week, Secretary of Defense Robert Gates said Washington would be open to having some kind of Russian presence at the planned missile defense sites in Europe.
He made it clear that could only happen with Czech or Polish approval. The next day, Czech Prime Minister Mirek Topolanek said the Russian military would not be permitted to inspect the sites, although he left the possibility of other Russian inspections open. Still, the plan gave instant ammunition to radar opponents.
The same day Gates spoke, Czech activists against hosting the U.S. system set off on a cross-country bus tour. Others have called for a nationwide referendum on the issue.
Jana Danihelkova, a 28-year-old who works in information technology, says because the Soviet Union occupied her country for two decades, she is wary about any foreign military presence in the Czech Republic, even troops from America, a close ally.
"I'm just afraid if it starts as one or two, then it could grow to 20, or 30," she says. "And that could turn into a well established presence that could be around forever."
Another U.S. offer to Moscow is to build the system but delay activating it - until there is concrete proof of a threat. Assistant Secretary of State Daniel Fried said that doesn't mean Moscow and Washington would have to agree on the threat.
"We would not give Russia a veto," he said. "We would not ask Russia's permission to turn it on."
Instead, he said Washington could share threat assessments with Russia. One threat benchmark several U.S. officials offer as an example is if Iran tested missiles that could reach Europe.
Getting Moscow on board might actually improve support for missile defense among some Czech politicians who fear offending Russia. Still, political analyst Jiri Pehe said any parliamentary vote would be close, and given upcoming U.S. presidential elections, it makes no sense to hurry.
He said it is "extremely inconvenient" for Czech politicians to "put their political futures on line in the name of the radar" if the project could be cancelled by the next American administration.
The U.S. is in talks with the Czech government over the radar installation, with an agreement and parliamentary vote possible by early next year.
Washington is also negotiating with Warsaw about hosting interceptor rockets for the missile shield. The Bush administration had hoped to wrap up an agreement with Poland by the end of this year. Parliamentary elections earlier this month, however, means the current government in Warsaw is on the way out. The new government is expected to focus on patching up relations with Russia, and not rush a missile defense.
Some political leaders said Poland needs to get concrete military benefits in exchange for allowing the U.S. to build the rocket site there. Analyst Jacek Zakowski expects Poland's new leaders to push Washington for real influence at the site, rather than just signing over land.
He said the amount of knowledge the Polish government will have about what goes on at the site and how much influence Warsaw will carry there is a "serious political problem" that has not yet been thoroughly debated.
U.S. measures proposed with Moscow in mind leave many in Warsaw and Prague feeling they, the potential hosts of the military hardware, are pawns in a familiar bilateral game.
One Czech activist says he'd quit fighting the installation if it were a NATO project instead.