Drawing on ideas favored by conservatives and stoked by “tea party” activists, House Republicans will unveil a manifesto Thursday that calls for cuts in government spending, repeal of the new healthcare law and a strict constitutional test for every proposed law, according to a draft.

The 21-page blueprint, called “A Pledge to America,” offers the most detailed picture yet of how Republicans plan to address national issues if they win a majority in the House in November, which prognosticators say is increasingly likely.

The GOP plan ignited a debate within conservative circles. Establishment Republicans embraced the agenda, but activists complained that it did not go far enough and omitted some of their key demands, such as a balanced budget amendment to the Constitution.

The plan treads lightly on hot-button social issues such as marriage and abortion that have been mainstays of past GOP agendas but are less likely than economic questions to motivate independent voters this fall.

The pledge contains no mention of proposals by leading conservatives and several GOP candidates to restructure Social Security and Medicare by using personal savings accounts, nor of other measures that voters have resisted.

But like the 1994 “Contract with America,” released weeks before that year’s midterm election swept Republicans to power, the 2010 manifesto is expected to provide a campaign platform to make the case that Republicans are ready to govern.

The White House sought to undercut the GOP rollout. Speaking at a fundraiser for congressional Democrats on Wednesday night in New York, President Obama said Republicans had ignored an idea popular with Americans who weighed in on the GOP’s own “America Speaking Out” website: ending tax breaks for corporations that ship jobs overseas.

The proposals, the president said, mask the Republican Party’s intent to return to the “exact same agenda” they pursued under former President George W. Bush.

The top Republican proposal is a familiar one: “Permanently stop all job-killing tax hikes” by extending the tax cuts enacted during the Bush administration that are set to expire in December. The White House wants to extend the reduced rates only for families earning less than $250,000 a year and individuals making less than $200,000, whereas Republicans want to extend them to higher-wage taxpayers as well.

Extending the tax cuts across the board would cost nearly $4 trillion over 10 years, according to congressional estimates. Eliminating the rates for the wealthy reduces the tab by about $700 billion.

In taking aim at what Republicans call " Washington’s out-of-control spending spree,” the plan advocates rolling back most federal spending to 2008 levels to save $100 billion, imposing a new cap on discretionary spending, and halting government hiring for nonsecurity employees.

On that issue, the party’s conservative flank parted ways with the pledge, saying House Republicans simply recycled promises that the party broke when it was in control and failed to tackle the tough decisions needed to limit government.

“Like a diet full of sugar, it will actually do nothing but keep making Washington fatter before we crash from the sugar high,” said Erik Erikson of the blog RedState.

Erikson noted that the plan did not call for a spending limitation amendment or a balanced budget amendment.

“It is just meaningless stuff,” Erikson wrote, calling the proposals “an illusion” that avoids real action against the size and scope of government.

But the influential conservative magazine National Review called the pledge a “shrewd” piece of work that would be difficult for Democrats to counter.

“It will help tremendously with independents who have been turned off by Democrats but [who] really needed an alternative GOP platform to support,” GOP strategist Ron Bonjean said.

Republicans promised to “repeal and replace” the administration’s signature legislative achievement, the healthcare law. Reintroducing past GOP proposals, they would allow consumers to purchase health insurance across state lines, expand personal health savings accounts, and prohibit government spending on abortion by permanently enacting the so-called Hyde Amendment.

One of the few references to social issues is in an opening vow “to honor families, traditional marriage, life, and the private and faith-based organizations that form the core of our American values.”

The plan proposes beefing up border security to fight illegal immigration, another contentious issue that has energized the party’s base but is only addressed in broad terms.

In one of the most significant signs of tea party influence, Republicans propose that any bill moving through Congress “include a clause citing the specific constitutional authority upon which the bill is justified.” The party blames costly programs on a “lack of respect” for constraints on government outlined in the Constitution.

On foreign policy, the plan calls for fully funding the missile defense system, enforcing tough sanctions on Iran and keeping terrorism suspects at Guantanamo Bay, Cuba. Obama has canceled a major missile defense program and wants to close Guantanamo.

The long-expected GOP plan will be released after a roundtable at a family owned business in Sterling, Va. It was crafted after several months of consultation with voters.

“We put thought into this,” said Rep. Pete Sessions of Texas, the chairman of the Republican campaign committee. “What we’re trying to do is point out ideas that Americans fully support, and view as American ideas that should not be lost.”

Unlike the 1994 “Contract with America,” which was essentially a 10-point to-do list, rank-and-file lawmakers saw in this document a broader governing strategy they could use on the campaign trail.

“It’s got some real meat on it,” said Rep. Jason Chaffetz (R- Utah), who noted simple promises like one to post bills online for three days before voting. “It’s a reflection that we’ve been listening.”

michael.memoli@latimes.com

lisa.mascaro@latimes.com