WASHINGTON (AFP) – The White House Friday savored a "big win" for President Barack Obama, after Congress backed his tax deal with Republicans, despite fierce opposition from sectors of his Democratic Party.

Top Obama aides also expressed confidence that two other big agenda items -- the repeal of a ban on gays serving openly in the military and a new nuclear arms reduction deal with Russia would also soon win Senate backing.

The rush of legislation in the previously log jammed Senate helped confound perceptions that Obama would be constrained after his Democrats got a pounding in mid-term elections and provided a road map for his dealings with a new Republican Congress next year.

The 858 billion dollar tax bill, which Obama was set to sign later Friday, includes an extension of tax cuts passed by ex-president George W. Bush and renews benefits for the long-term unemployed.

But some Democrats are furious that it extended tax breaks for the wealthiest Americans and rolled back inheritance tax on the richest estates.

"I think it is a big win for the president," White House spokesman Robert Gibbs said.

"The agreement is one that will help the economy and one that will help those on the short end of the economy (who) have lost their jobs."

Gibbs said that the White House was also increasingly hopeful that the bid to scrap the "Don't Ask, Don't Tell" provision on gays in the military and the START nuclear disarmament treaty would also pass before the end of the year.

Obama's Democratic allies in the US Senate have set the stage for a critical weekend test vote on the bill.

Supporters fear they will lose their best chance in years of overturning "Don't Ask, Don't Tell" when a new US Congress musters in January with Republicans -- who largely oppose repeal -- in charge of the House.

The Senate is also forging ahead on Obama's top foreign policy priority, the new Strategic Arms Reduction Treaty (START) with Russia, even as Republicans sought to put off a vote until next year or even kill the deal.

Top US military officials rebuffed Republicans charges that the pact will cripple US missile defense plans, as Democratic Senate Majority Leader Harry Reid set the stage for a likely ratification vote next week.

"We need START and we need it badly," General James Cartwright, the vice chairman of the Joint Chiefs of Staff, told reporters, stressing the treaty included "no prohibitions to our ability to move forward in missile defense."

The agreement -- which has the support of virtually every present and past US foreign policy or national security heavyweight -- restricts each nation to a maximum of 1,550 deployed warheads, a cut of about 30 percent from a limit set in 2002, and 800 launchers and bombers.

The accord would also return US inspectors who have been unable to monitor Russia's arsenal since the treaty's predecessor lapsed in December 2009.

The House of Representatives sent the tax deal to Obama late on Thursday by a 277-148 vote, a day after the Senate passed the package by an 81-19 margin.

The bill is "good for growth, good for jobs, good for working and middle-class families, and good for businesses looking to invest and expand their work force," Treasury Secretary Timothy Geithner said in a statement.

But some angry Democrats were dismayed.

"This measure does not create a single job or stimulate the economy in any way," said number-three Democratic Representative James Clyburn, who urged lawmakers to "restore some fairness to the tax code."

Democrat Linda Sanchez from California called the measure "reckless," and Democrat Jay Inslee from Washington state derided it as "deja-voodoo economics."

Obama -- who campaigned on a vow to let tax cuts lapse on income over 250,000 dollars for families or 200,000 dollars for individuals -- dropped that insistence after the election and urged fellow Democrats to do the same.