The bill could be passed by the Senate and sent to the House this week. The Senate voted 83-15 on Monday evening in a test procedural vote to advance the package, which would provide a two-year reprieve from tax increases scheduled to take effect on 1 January at all income levels. The tally easily surpassed the necessary 60 of 100 Senate votes needed to clear a procedural hurdle and move to a final vote.

“This proves that both parties can in fact work together to grow our economy and look out for the American people,” Obama said. “I recognise that folks on both sides of the political spectrum are unhappy with certain parts of the package and I understand those concerns. I share some of them. But that’s the nature of compromise.”

The tax deal moved forward as Congress winds down a final session before the Democrats cede their majority to Republicans in the House of Representatives in the next Congress. It convenes in early January.

The Senate will remain under Democratic control, but the president’s party will hold a much diminished majority.

It was that reality, the result of a Republican landslide in congressional elections last month, that prompted Obama to strike the tax deal with Republicans.

The deal marks a test of how Obama will manage to govern without his party in control of both houses of Congress. His readiness to reach accommodation with the opposition party likely will set a pattern for the final two years of his term.

Despite strong criticism from fellow Democrats, Obama has made passage of the bill a key year-end priority, calling it essential for the economy as it struggles to recover from the worst recession in decades.

The compromise that came to a procedural vote in the Senate late Monday afternoon would extend Bush-era tax cuts for all income brackets despite Obama’s historic opposition to keeping lower rates in place for U.S. households earning more than $250,000 a year.

Faced with the prospect of higher taxes across all income brackets, Obama chose compromise. In return, Republicans dropped opposition to an extension of payments to the long-term unemployed. The deal would guarantee those payments continue for 13 months.

Additionally, the plan would reduce payroll taxes by 2% for one year. Those assessments go to fund Social Security, the federal pension system for older and disabled Americans.

The bill’s overall cost, estimated at $858 billion over two years, would be added to already huge federal deficits.

House Democrats were scheduled to meet in a closed-door caucus yesterday evening to discuss the package. Last week, House Democratic leaders said they would not schedule a vote on the tax bill without changes to make it less generous to the wealthy.

The main sticking point is a big expansion of the ceiling at which estates are taxed. The leader of the House, Speaker Nancy Pelosi, initially called that part of the deal “a bridge too far” and has been joined in hot opposition to that part of the measure by liberal Democrats in the lower house.

The package Obama negotiated would set the top rate at 35% and exempt the first $5 million of an individual’s estate. Couples could exempt $10 million. Without the deal, the estate tax was scheduled to return next year to a top rate of 55% for estates larger than $1 million for individuals and $2 million for married couples.

In his remarks, Obama called the deal “a substantial victory for middle class families across the country.” He gave no indication he was willing to accept further changes to the plan he negotiated with senior Republicans.

“I understand those concerns,” he said of objections from some of his usual allies in Congress. “I share some of them. But that’s the nature of compromise, sacrificing something that each of us cares about to move forward on what matters to all of us.”

House Majority Leader Steny Hoyer said on Monday that he believed the tax deal passed by the Senate would come to a vote in the lower chamber of Congress, despite strong reservations by House Democrats.

“I think we’re going to have a vote on the Senate bill, with possible changes,” Hoyer said. “We may have it with amendments. We’ll see what the process is.”

Rep. Chris Van Hollen, also a member of the Democratic leadership in the House, predicted liberals, including Pelosi, would not “hold this up” despite roiling anger among progressives.

Senate Republicans, however, warned that any changes to the estate tax provisions could unravel the deal.

“If the House Democratic leadership decides to make partisan changes, they will ensure that every American taxpayer will see a job-killing tax hike on 1 January,” said Senate Republican Leader Mitch McConnell of Kentucky.