WASHINGTON (AP) -- Eager to show who's now in charge, the House's new Republican majority plans to vote to repeal President Barack Obama's landmark health care overhaul before he even shows up in their chamber to give his State of the Union address.

Obama urges Republicans to put politics aside, The Skanner News Video here

Dramatic as that early showdown promises to be -- the vote will be Jan. 12, Republicans said Monday -- it will be just the first in a series of struggles expected to play out in the next few months. Obama returns Tuesday from his holiday vacation, fresh off lame-duck legislative victories late last year, and Republicans will be sworn in Wednesday, primed to challenge him after gaining House control in last fall's elections.

Full repeal of the health care law is still a long shot. The House vote would be just the first, easiest step. But House Republicans vow they will follow up with dozens of attempts to hack away at what they derisively call ``Obamacare.''

The strategy is not risk-free for the Republicans, who won't have a replacement plan of their own ready by the time of the repeal vote. But they say there's no time to lose.

Senate Democratic leaders are sending their own ``you-don't-scare-me'' message. In a letter Monday to House Speaker-to-be John Boehner, they served notice that they'll block

any repeal, arguing it would kill popular provisions such as improved prescription coverage for Medicare.

Beyond the early health care vote, emboldened Republicans are straining to challenge the president's spending priorities, setting up likely conflicts over the budget and the country's debt ceiling. Those votes will be early tests of how the president will maneuver with a divided Congress, as both he and Republicans look ahead to the next elections.

Most likely, both parties will carry the main issues of the health care debate into the 2012 campaign, when Obama is expected to seek a second term against a Republican challenger, and House and Senate control will be up for grabs again.

``It's not going to be easy; it's going to be a long, hard slog,'' said Rep. Steve King, R-Iowa, an early leader in the health care repeal drive. The quick thumbs-down vote by the House will have ``tremendous utility and value,'' King said, but it may take electing a Republican president in Obama's place to accomplish the overall goal.

All the while, the Obama administration intends to keep putting into place the law's framework for covering more than 30 million uninsured people. Ultimately, Obama still has his veto pen, and Republicans aren't anywhere close to the two-thirds majorities they   would need to override

``Repeal and replace'' worked as a campaign slogan to motivate voters concerned about the growing reach of government under Obama. But a single-minded focus on repeal could backfire as a Republican governing strategy. Polls show that some parts of the law are popular, and many Americans would have wanted even bigger changes.

Look for Republicans to try to deny money for the government to carry out the law. They'll also attempt to strip out sections of it, such as a new long-term care program. And they'll move to strengthen restrictions on funding for abortions.

It's far from clear that they'll be able to prevail in those efforts either. There's talk that an   effort to deny funding could escalate to the point of a possible government shutdown, and no one seems eager for that.

``I don't think the health issues will cause anything dire in the way of a government shutdown,'' said economist Robert Reischauer, president of the Urban Institute think tank. ``There are other things on the agenda besides health care, namely broader budget issues that have to be dealt with.''

The two parties may be able to get a deal on some limited fixes, like repealing an income tax reporting requirement that small business is calling a paperwork nightmare.

At the White House, spokesman Reid Cherlin said Obama would have no qualms about delivering his State of the Union speech to lawmakers who've just repudiated his signature accomplishment, one that Democrats compare with the establishment of Social Security and Medicare. The president ``feels pretty confident about defending the health care law,'' Cherlin said.

Senate Democrats agree. In Monday's letter to Boehner, Majority Leader Reid and top lieutenants said repeal would undermine improvements already on the books, such as deep discounts on brand-name drugs for Medicare recipients who have fallen into a coverage gap called the ``doughnut hole.''

``This proposal deserves a chance to work,'' the Democratic leaders said. ``It is too important to be treated as collateral damage in a partisan mission to repeal health care.'' The law would gradually close the coverage gap.

Democrats are preparing other counterattacks.

Rep. Peter Welch, D-Vt., said Monday he will try to force the House to vote separately on the Medicare drug benefits and other popular provisions, including one that allows adult children to stay on their parents' coverage until they turn 26. That could put Republicans in an awkward bind.

Other supporters of the health care law have launched a ``drop it or stop it'' campaign, challenging Republicans who vote to repeal the overhaul to also give up the government-funded health insurance provided to members of Congress.

``It's hypocrisy, their willingness to take health care from the U.S. Congress, while they're denying it to their constituents,'' said Ethan Rome, executive director of Health Care for America NOW, a coalition of the law's backers.

Republicans say that's nonsense: Lawmakers are only accepting the same employer-sponsored health care coverage available to other federal workers.

They may be more vulnerable on another score. The House vote will be to simply repeal the health care law. The ``replace'' part of the GOP slogan will be delegated to several committees, charged with developing an alternative as the year goes on. That can be a laborious process, one that produced plenty of disagreements and embarrassments for Democrats when they were in control.

It's a risk worth taking, says Rep. King. ``I do not believe that you can leave any of Obamacare in the law,'' he said. ``To pick and choose would start endless squabbles. If there are components of Obamacare that have merit, they can be reintroduced as part of a replacement process.''

Finally, there's a wild card: the courts. Challenges to the constitutionality of the health care law are working their way toward the Supreme Court. Opponents say Congress overstepped its authority by requiring most Americans to carry health insurance, effective in 2014. The case may take a couple of years, and it could change everything.