U.S. Senator John Kerry (D-MA) (L) and Senator Richard Lugar (R-IN) smile during a news conference after the Senate ratified the START nuclear arms reduction treaty at the US Capitol in Washington, December 22, 2010.

He stressed the treaty as a national security imperative and warned that failure to pass would harm warming relations with Russia, citing Russia's cooperation on issues like Iran's nuclear program and the Afghanistan war. He also reminded that the treaty had gone through 18 hearings after it was sent to the Senate floor in May, with nearly 1,000 questions having been asked and answered.

He also used the venue of Nov. 19-20 NATO summit in Lisbon, Portugal to drum up broad support from allies.

Vice President Joe Biden, Secretary of State Hillary Rodham Clinton, Defense Secretary Robert Gates and Chairman of the Joint Chiefs of Staff Mike Mullen all played their part in soliciting votes.

Six former Republican secretaries of state and former Presidents George H.W. Bush and Bill Clinton, among others, threw their weight behind the treaty signed by Obama in April with Medvedev, which caps the deployed nuclear warheads in each state to no more than 1,550 over seven years, a cut of 30 percent over the current ceiling of 2,200 set in 2002, limits the number of deployed ballistic missiles and nuclear bombers to no more than 700 each, and sets up a mechanism for verification and inspection.

Opponents alleged that the treaty offers too many concessions to Russia, weakens U.S. ability to employ missile defense technology and has insufficient procedures to verify Russia's adherence.