The first move will come Friday, when the House begins the process of repealing the new health-care law. House leaders will then quickly begin to identify tens of billions of dollars in proposed spending cuts and to ease regulations that businesses find burdensome.

Much of what Republicans do will be symbolic, given that Democrats still control the Senate and the White House. But the quick action will allow Rep. John A. Boehner (R-Ohio), the incoming speaker, and House Republicans to follow through on campaign pledges and to try to establish their party as a bulwark against what they see as an out-of-control government.

Recognizing the limits of their power, Republican leaders said they will follow their initial aggressive stance with efforts to force Obama into what they consider principled compromises. Those would most likely come with attempts to cut federal spending and spur job growth, two agenda items that both parties have set as priorities.

"This is a two-way street going on here, and results are going to be judged through the prism of whether jobs are created and whether spending is cut and the deficit is brought back under control," Rep. Eric Cantor (R-Va.), the incoming House majority leader, told reporters Tuesday. "And it is as much the responsibility of this administration as well as the Senate to join with us in echoing what we heard in the last couple months."

While the Democratic majority in the Senate was diminished in November, the party still holds a 53-to-47-seat edge, giving Majority Leader Harry M. Reid (D-Nev.) the votes he'll need to block Republican legislation coming from the House.

More bipartisanship?

But the upper chamber's new margin could force the two sides into more-bipartisan talks than the narrow negotiations held in 2009 and 2010. Then, Democrats needed to win over just a couple of Republicans to overcome filibusters, but now Democrats need at least seven Republicans - and the GOP needs at least 13 Democrats - to maneuver.

"Any solution now is going to have to have at least 10 to 20 senators from the other side," said Sen. Lamar Alexander (Tenn.), the No. 3 Republican leader.

That will probably make Minority Leader Mitch McConnell (R-Ky.) a critical player in the coming months, since he could either engineer bipartisan agreements or be a deal-breaker.

Senate Republicans are looking ahead to a pair of opportunities in the next several weeks in which McConnell could re-create his role in negotiating the broad bipartisan deal last month to extend the Bush-era tax cuts. Party leaders said they hope to use the March 4 expiration of the temporary measure that funds the government, as well as the need to lift the federal debt ceiling above $14 trillion, to extract concessions from Obama.

The starting point for spending cuts will be in the House, where Boehner has established a goal of rolling back spending to 2008 levels. That would mean a reduction of more than $60 billion for the remainder of the fiscal year - a number that many Democrats consider politically difficult to achieve if Republicans exclude cuts to the Pentagon and homeland defense programs, as they have said they would.

"The pressure is going to be on them," Sen. Charles E. Schumer (D-N.Y.) said Tuesday, noting the GOP resistance to specifying which agencies would have spending slashed and by how much. For now, House Republicans are optimistic that November's 63-seat gain has given them the political leverage to wield their budget knives. "It's going to be easier to cut spending than people think," said Rep. Paul D. Ryan (R-Wis.), the incoming Budget Committee chairman.

Debt-ceiling showdown

An early moment of brinksmanship for all sides is likely to be the debt-ceiling vote. Some Republicans have suggested resisting the measure until Obama agrees to steep spending cuts, while administration officials warn that such an action could result in the government defaulting on its debt, wreaking havoc on international markets.

Robert Bennett (R-Utah), a retiring senator and close friend of McConnell's, called his Kentucky colleague "the perfect leader for this kind of atmosphere," someone who can bridge divides and advance the GOP agenda, if only a piece at a time. However, Bennett said, the "$64 billion question" is how the 87 new House Republicans will operate after an aggressive fall campaign in which many pledged to challenge the president, not compromise with him.

Though the vote to repeal the Democrats' health-care law will be the first action of the new House, the real showdown is likely to come later in the year, when Republicans try to halt funding for the legislation through cuts in annual spending bills.

The mandate that individuals have insurance plans, for instance, would probably compel the IRS to hire thousands of new agents to monitor whether people are complying - an expenditure that House Republicans stand ready to block.

In the short run, Republicans will settle for the repeal vote next Wednesday, a simple two-page declaration that will set a political marker for where they stand.

"The imperative now is to make sure we send a repeal bill across the floor reflecting our willingness to listen to the American people," Cantor said.