WASHINGTON As they seek to make good on their campaign promise to roll back President Barack Obama's health care overhaul, the incoming Republican leaders in the House say they intend to use their new muscle to cut off money for the law, setting up a series of partisan clashes and testing Democratic commitment to the legislation.

Republicans, who will control the House starting in January but will remain in the minority in the Senate, acknowledge that they do not have the votes for their ultimate goal of repealing the health law, the most polarizing of Obama's signature initiatives.

They said they hope to still use the power of the purse to challenge key elements of the law, forcing Democrats - especially those in the Senate who will be up for re-election in 2012 - into a series of votes to defend it.

Republican lawmakers said, for example, that they would propose limiting the money and personnel available to the Internal Revenue Service, so the agency could not aggressively enforce provisions that require people to obtain health insurance and employers to help pay for it. Under the law, individuals and employers who flout the requirements will face tax penalties.

Republican leaders said they plan to use spending bills to block federal insurance regulations to which they object. And they will try to limit access to government-subsidized private health plans that include coverage of abortion - one of the most contentious issues in congressional debate over the legislation.

Given their slim majority, Senate Democrats must stick together if they want to avoid sending Obama spending bills and other legislation that he would feel compelled to veto, setting up the prospect of a broader deadlock and, in an extreme situation, a government shutdown.

The House Republican whip, Rep. Eric Cantor of Virginia, described the strategy this way: "If all of Obamacare cannot be immediately repealed, then it is my intention to begin repealing it piece by piece, blocking funding for its implementation and blocking the issuance of the regulations necessary to implement it."

"In short," Cantor said, "it is my intention to use every tool at our disposal to achieve full repeal of Obamacare."

The Senate Republican leader, Mitch McConnell of Kentucky, said he, too, wanted to shut off money for the new law.

Obama has made clear that he will fight to preserve all the fundamental elements of the law. When asked whether the president would veto legislation to cut off money, his spokesman, Robert Gibbs said, "I don't think we'll get to that."

Both sides said they were determined to avoid a government shutdown like the one in 1995 that, by many accounts, did political damage to House Republicans and Newt Gingrich, who was then speaker.

Anticipating the Republican assault, White House officials said Obama would emphasize how the law protects consumers and gives them more control of their insurance. Administration officials are working with Senate Democrats to arrange hearings at which consumers would explain how they have already benefited from the law.

One of the president's strongest allies is Sen. Tom Harkin, D-Iowa, an architect of the law.

Harkin said he would "fight any attempt to defund the law or repeal its consumer protections." He is well placed to lead such resistance. He is chairman of the Senate health committee and chairman of the Senate Appropriations subcommittee responsible for health programs.

The variety of restrictions Congress can impose in spending bills is almost unlimited. By attaching the restrictions to appropriations bills, House Republicans can force negotiations with the Senate. The Hyde amendment, restricting the use of federal money to pay for abortion, began as such a rider more than 30 years ago.