A Republican senator is blocking President Barack Obama's nominee to become ambassador to Russia over suspicions the U.S. might provide Moscow with sensitive missile defense information.
The administration says it has no plans to provide such data. But it says the assurances sought by Sen. Mark Kirk, R-Ill., are so broad, they would prevent any substantial cooperation on missile defense.
The dispute with Kirk further complicates the Obama administration's efforts to get U.S.-Russian relations back on track at a time of increased tensions over missile defense.
It also has political overtones ahead of next year's elections. The White House considers improved relations with Russia, including the signing of a major arms reduction treaty, to be one of the big foreign policy successes of Obama's presidency. Republicans have accused Obama of granting too many concessions to Russia and getting little in return.
Kirk is holding up the nomination of Michael McFaul, a senior adviser to Obama on Russia. In an interview with The Associated Press, Kirk said he wants written assurances that the United States will not provide Russia with any currently classified information on the missile defense system.
Kirk said he is particularly concerned that the administration could offer Russia data on the speed of interceptors planned for Europe in order to ease Russian fears that the system could knock out Russian ballistic missiles.
He said he also is concerned about Russia's "record of espionage and cooperation and dialogue with Iran." He said precise data on the interceptor speeds could help Iran evade the U.S. defenses. The U.S. insists its missile interceptors are aimed at countering a threat from Iran.
The administration says that while it is not considering such an offer, it does not want to limit its options by ruling out any exchange of sensitive information they say would be essential for any substantial missile defense cooperation.
"In the future, some classified information exchange may benefit the United States," White House spokesman Tommy Vietor said in a statement.
U.S. missile defense plans in Europe have been one of the touchiest subjects in U.S.-Russian relations going back to the administration of Obama's predecessor, George W. Bush.
One of Obama's earliest moves to ease tensions was the administration's 2009 announcement that it would revamp Bush's plan to emphasize shorter-range interceptors. Russia initially welcomed that move, but has more recently suggested that the new interceptors could threaten its missiles as the U.S. interceptors are upgraded.
U.S. talks with Russia over missile defense cooperation have nearly broken down. Russia recently threatened to target missiles at the U.S. missile defense systems in Europe and just commissioned a radar in Kaliningrad, near the Polish border, capable of monitoring missile launches from Europe and the North Atlantic.