EXCLUSIVE: U.S. to stop counting new missiles in Russia

Still, critics say ties are not at a level where Washington can fully trust Moscow.

“For the first time in 15 years, an extensive set of verification, notification, elimination and other confidence-building measures will expire” on Saturday, Sen. Jon Kyl, Arizona Republican, said on the Senate floor late last month, suggesting that START should have been extended.

Mr. Kimball said another reason the Bush administration should take at least some responsibility for losing access to Votkinsk is that it “did not object to Russia’s development of the RS-24 and did not favor the continuation of other types of legally binding verification provisions based on those in START.”

“Senator Kyl was not on the floor of Senate railing against the Bush administration’s decision not to continue essential START monitoring and verification provisions back in 2008, but now he’s complaining that the Obama administration is not doing enough to maintain effective monitoring of U.S. and Russian strategic nuclear weapons,” Mr. Kimball said. “He was against it before he was for it.”

A senior aide to Mr. Kyl said the senator always cared about verification, but he is more vocal now because Mr. Obama wants to cut the two countries’ nuclear arsenals well below Mr. Bush’s target level of 1,700 to 2,200 warheads.

“If you are going to predicate the prudence of the cuts on the Russians’ [compliance], you have to make sure you have high degree of confidence” that they are abiding by the limits, he said.