WASHINGTON — Republicans on Thursday began plotting strategy for the next Congress by vowing to be unified and relentless in their insistence that this year’s health care overhaul be repealed and that most domestic spending be frozen or cut drastically.

The GOP, which gained at least 60 seats in the House of Representatives and six in the Senate in Tuesday’s election, showed no appetite for bipartisan cooperation.

“”The mandate for change is directed at the other guys,”” said Senate Republican leader Mitch McConnell of Kentucky. “”We are right where we have been.””

Where they’ve been for the past two years is marching mostly in lockstep on issues central to the Republican platform, such as health care, global warming and spending — and against the Democrats’ agenda.

Don’t look for much change, GOP leaders said.

They’ll want Bush-era tax cuts extended permanently. “”The best thing we could do for families and job creation is to extend the current rates as soon as possible for as long as possible,”” said Rep. Dave Camp, R-Mich., who is expected to chair the House Ways and Means Committee.

They’ll want votes on repealing the health care overhaul, even though they know that President Barack Obama would veto any such effort.

McConnell conceded that his party won’t be successful right away on health care. But, he said, “”We can compel administration officials to attempt to defend this indefensible health spending bill and other costly, government-driven measures.””

Democrats fired back.

“”Republicans have always been the party of putting big business over the middle class,”” said Jim Manley, spokesman for Senate Majority Leader Harry Reid of Nevada, “”and they are wasting no time in trying to jam through favors for big corporations at the expense of hardworking families who are struggling to make ends meet.””

Theoretically, two potential cracks in Republican unity could emerge — from the right and the middle — but given the solidarity in GOP ranks over the past two years, chances that their ranks will splinter now appear slim.

Still, here’s how it could happen: The tea party movement backed an estimated 110 winning House Republicans, but at least three of its seven Senate candidates lost. Rep. Michele Bachmann of Minnesota, a tea party favorite, will challenge Texas Rep. Jeb Hensarling for the fourth-ranking House Republican leadership position. Hensarling has the backing of Rep. Eric Cantor, R-Va., the likely House majority leader. Their showdown could rupture GOP ranks.

Analysts warned that Republicans need to be careful with tea party backers.

“”This is trouble for the party,”” said GOP pollster Bill McInturff. He found about one-third of Republican voters say they’re not tea party people, while another third are Republican but “”really think of myself as a tea party person.””

The final third says, “”I’m a Republican and tea party, but when you ask, I think myself more as a Republican.””

The danger to the GOP is that a rift might emerge between tea party purists and more established Republican lawmakers schooled in compromise.

However, Sal Russo, the Sacramento, Calif.-based political guru behind the Tea Party Express, said the movement is unified over reining in the growth and expansion of the federal government. Tea party backers are politically practical, he said, to a point.

“”I think most people recognize that you have to give to get sometimes,”” Russo said. “”What we’re saying is we expect 100 percent fidelity on our issue — you’ve got to rein in the scope and the range of the federal government.””

The other potential dent in Republican unity could come from the few remaining GOP moderates. Up for re-election in 2012 are Sens. Scott Brown of Massachusetts, Richard Lugar of Indiana and Olympia Snowe of Maine.

Still, since only 41 votes are needed in the 100-member Senate to avoid having debate shut down, and the new Senate will have at least 46 Republicans, the GOP moderates probably won’t be needed for close votes they’re not comfortable with.

In the House, where 218 votes are needed for a majority, current projections show the GOP winning 239 seats, so the GOP leadership could lose 20 or more Republicans and still win.

One centerpiece of the Republican strategy is to build for 2012, when 21 Senate Democrats, two independents who caucus with the Democrats and 10 Republicans face re-election.

“”We have a reasonable shot of getting a majority in the near future,”” McConnell said.

As part of that push, one of his party’s major themes will be to build a case that Democrats are woefully out of touch.

That’s particularly important to the tea party loyalists.

“”Believe me, they’re in a no-compromise stance,”” said McInturff. “”They don’t want engagement with the president, they don’t want to work across party lines; they want now-former Speaker Pelosi’s agenda totally and irrevocably stopped and reversed.””

That’s the theme that congressional leaders are stressing.

Democrats “”set about dismantling the free market, handing out political favors at taxpayer expense, expanding government and creating a more precarious future for our children,”” McConnell charged.

“”In other words, Democrat leaders used the crisis of the moment to advance an agenda Americans didn’t ask for and couldn’t afford. And then they ignored and dismissed anyone who dared to speak out against it.””

He also had a warning to Republicans not to get too haughty: “”Voters didn’t suddenly fall in love with Republicans; they fell out of love with Democrats.””