Senate Democrats secured the backing of a significant number of Republicans in a crucial test vote Wednesday on a new U.S.-Russia arms control treaty — President Barack Obama's top foreign policy priority.

The 66-32 vote to take up the treaty bolstered White House and senior Democrats' claims that they will have the two-thirds majority needed to ratify it before Congress adjourns for the holiday, even though a majority of Republicans prefer waiting until next year.

Nine Republicans, including Sen. John McCain of Arizona, Obama's 2008 presidential rival and a top lawmaker on national security issues, supported moving ahead on the treaty now.

Obama has said he is prepared to delay a planned holiday vacation until the treaty is completed, elevating the measure to year-end, must-do status along with the tax deal he cut with Republicans. Democrats are determined to push the treaty through the Senate in hopes of giving Obama a foreign policy victory before the GOP grabs more power next year.

"We believe we should stay here as long as it takes to get this treaty ratified, and we are prepared to do so," said Foreign Relations Committee Chairman John Kerry, D-Mass.

Still, several Republicans, led by Sen. Jon Kyl, R-Ariz., objected to considering the treaty in the waning days of Congress' lame-duck session, insisting the Senate should delay action until it has more time. Sens. Lamar Alexander of Tennessee and Saxby Chambliss of Georgia said they could support the treaty but not under the current timetable. Alexander told reporters it was "reckless."

Speaking for the treaty before Democrats took their turn, Republican Sen. Richard Lugar of Indiana said the treaty "will enable American teams to return to Russia to collect data on the Russian arsenal and verify Russian compliance. These inspections greatly reduce the possibility that we will be surprised by Russian nuclear deployments or advancements."

U.S. weapons inspections ended a year ago with the expiration of the 1991 arms control treaty.

Angry accusations marked the hours before the vote as Republicans threatened to force the treaty, signed in April, to be read aloud in the Senate, which would have delayed consideration. The White House called the GOP out on the maneuver, with press secretary Robert Gibbs assailing it as a "new low in putting political stunts ahead of our national security."

Gibbs singled out Sen. Jim DeMint, R-S.C., for possible delaying tactics.

The heated rhetoric quickly gave way to a more sober analysis. Senate Minority Leader Mitch McConnell, R-Ky., said of the talk about reading the treaty, "Our view is that is not essential."

Several Republicans had argued that the limited time available in the lame-duck session made it difficult to give the treaty the consideration it deserved. Twenty-two Republican senators signed a letter Dec. 2 calling for debate on the treaty to be delayed until next year.

Proponents of the treaty cite the renewed weapons inspections and say it would keep the two biggest nuclear powers on the path to reducing their arsenals. Opponents have asserted it would limit U.S. missile defense options and argued that it has insufficient procedures to verify Russia's adherence to the treaty.

In an argument linked to national security, White House officials have contended that the U.S. must show credibility in its improved relations with Russia. Its help with supplies for the war in Afghanistan and its ability to help pressure Iran over its nuclear ambitions have proven important to U.S. security, officials say.

The treaty has pitted moderate Republicans against hard-line conservatives, with potential 2012 challengers to Obama making opposition a requirement for anyone weighing a bid for the GOP presidential nomination. Lining up in opposition are Sarah Palin, Mitt Romney, Newt Gingrich, Minnesota Gov. Tim Pawlenty and Sen. John Thune of South Dakota.

Backing the treaty are former Presidents George H.W. Bush and Bill Clinton and several secretaries of state and defense from Republican and Democratic administrations, including Condoleezza Rice.

Supporters are pushing for ratification in this legislative session because prospects for passage will dim when the Democrats' majority shrinks by five senators in January. The Constitution requires approval by two-thirds of the Senate to ratify a treaty.

Obama signed the treaty with Russian President Dmitry Medvedev in April. It would allow each country 1,550 strategic warheads, down from the current ceiling of 2,200.