WASHINGTON (AP) — The Senate on Wednesday ratified an arms control treaty with Russia that reins in the nuclear weapons that could plunge the world into doomsday, giving President Barack Obama a major foreign policy win in Congress’ waning hours.

Thirteen Republicans broke with their top two leaders and joined 56 Democrats and two independents in providing the necessary two-thirds vote to approve the treaty. The vote was 71-26.

The accord, which still must be approved by Russia, would restart onsite weapons inspections as successors to President Ronald Reagan embraced his edict of “trust, but verify.”

Vice President Joe Biden presided over the Senate and announced the vote. Secretary of State Hillary Rodham Clinton observed the vote from the Senate floor. Both had lobbied furiously for the treaty’s approval.

“The question is whether we move the world a little out of the dark shadow of nuclear nightmare,” Foreign Relations Committee Chairman John Kerry, D-Mass., said to his colleagues moments before the historic tally.

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Calling the treaty a national security imperative, Obama had pressed for its approval before a new, more Republican Congress assumes power in January.

The Obama administration has argued that the United States must show credibility in its improved relations with its former Cold War foe, and the treaty was critical to any rapprochement. The White House is counting on Russia to help pressure Iran over its nuclear ambitions.

The New START treaty, signed by Obama and Russian President Dmitry Medvedev in April, would limit each country’s strategic nuclear warheads to 1,550, down from the current ceiling of 2,200. It also would establish a system for monitoring and verification. U.S. weapons inspections ended last year with the expiration of a 1991 treaty.

“START” stands for Strategic Arms Reduction Treaty.

Obama overcame the opposition the Senate’s top two Republicans — Minority Leader Mitch McConnell of Kentucky and Jon Kyl of Arizona, the GOP point man on the treaty.

Peeved by the Democrats’ interruption of the eight days of treaty debate for other legislation, McConnell accused the White House of politicizing the process.

McConnell said national security was the main concern, “not some politician’s desire to declare a political victory and hold a press conference before the first of the year.”

The ratification was a turnaround for a treaty whose fate was uncertain just a month ago. Conservatives railed that the pact would limit U.S. options on missile defense, lacked sufficient procedures to verify Russia’s adherence and deserved more time for consideration than the abbreviated postelection session.

Republican Sen. Mark Kirk of Illinois, who won Obama’s Senate seat, dismissed the treaty for imposing “marginal reductions in the Russian arsenal.”

The fierce opposition diminished quickly as former Presidents George H.W. Bush and Bill Clinton, six former Republican secretaries of state and much of the nation’s military and foreign policy experts called for the treaty’s ratification.

Defense Secretary Robert Gates and Joint Chiefs of State Chairman Adm. Mike Mullen pressed for approval, with Mullen simply telling senators earlier this week, “the sooner, the better.”

Weeks after Republicans routed Democrats at the polls — seizing control of the House and strengthening their numbers in the Senate — Obama has prevailed in securing overwhelming bipartisan approval of a tax deal with Republicans, getting repeal of the 17-year-old ban on openly gay military members and winning approval of the treaty.

The treaty capped a hefty yearlong record of legislation for the Democratic-controlled Congress and Senate Majority Leader Harry Reid, D-Nev. — a massive overhaul of the health care system, new financial regulations and a food safety bill as well as the postelection measures.

The treaty vote exposed divisions within the Republican Party that could stretch into the 2012 presidential and congressional elections. Obama got the treaty with the help of several GOP Senate moderates who split with possible White House hopefuls, some of the fiercest critics of the accord.

Former Massachusetts Gov. Mitt Romney opposed the pact; Sen. Scott Brown, R-Mass., who faces re-election in 2012, voted for it. Former Alaska Gov. Sarah Palin said the treaty was not in the country’s interest; Sen. Lisa Murkowski, R-Alaska, backed it. Former House Speaker Newt Gingrich described it as an “obsolete approach that’s a holdover from the Cold War;” Sen. Johnny Isakson, R-Ga., supported it.

Copyright 2010 The Associated Press.