WASHINGTON (AP) - Republicans are pressing ahead with one of the most ambitious and risky long-term spending agendas in memory, yet the dozen or so potential White House hopefuls are nearly invisible on the issue.
They can't stay on the sidelines for long, however. The contentious debate will rope them in on terms they might find hard to control.
The triumph of tea party candidates in 2010 pumped new urgency into a long-brewing Republican Party push for major cuts in domestic and benefit programs, including Medicare and Social Security.
In the absence of a Republican president or clear-cut party leader, a little-known congressman from Wisconsin seized the initiative. Backed by most House Republicans, Rep. Paul Ryan, the House Budget Committee chairman, wrote a far-reaching spending plan that right away framed the debate on Capitol Hill.
His proposal for the budget year that begins Oct. 1 calls for cutting spending by $5.8 trillion over 10 years. Ryan, R-Wis., would reduce tax rates for corporations and the wealthy, and eliminate various tax loopholes.
The blueprint aims to convert Medicare, the health insurance program for older people, into a subsidy or voucher program. Many probably would pay more for medical services.
Medicaid, which helps the poor and disabled, would become a state-run block grant program, a shift that would reduce federal spending by billions of dollars.
Democrats quickly pounced.
"It doesn't reform Medicare. It deforms and dismantles it," said Rep. Chris Van Hollen of Maryland, the top Democrat on the House Budget Committee. As for Medicaid, he said, the budget "rips apart the safety net" for the poor and elderly.
Expect similar criticisms in 2012 the presidential contest, which is why Republican contenders must approach Ryan's plan with caution.
Ryan's proposal for 2012 and beyond is unrelated to Congress's testy battle over the current year's budget fight, which nearly led to a government shutdown at the end of this past week.
Attention now turns to Ryan's plan and the fate of taxes, spending and the social safety net over the long term.
"Paul Ryan is going to define modern conservatism at a serious level," former House Speaker Newt Gingrich said on the radio show hosted by Bill Bennett, President Ronald Reagan's education secretary. "The general shape of what he's doing will define 2012 for Republicans."
Gingrich, who headed an ill-fated congressional bid to revamp Medicare in 1995, is preparing for a presidential run.
Scott Reed, a Republican strategist who managed Bob Dole's 1996 GOP presidential campaign, said Ryan's budget proposal "will drive the debate through the nominating process and into much of the general election." He said Ryan "has filled this huge policy void in the party with this very bold set of ideas."
Presidential contenders usually like to be the ones proposing bold solutions to pressing problems, even if it's Congress's job to pass budget bills. But Ryan has stolen that thunder, much as Republican governors in Wisconsin, New Jersey and Ohio have overshadowed the presidential field in the GOP campaign against government labor unions.
For now, the potential presidential candidates are keeping a low profile on the issue. Several have offered vague praise for Ryan, leaving themselves room to maneuver.
Former Massachusetts Gov. Mitt Romney applauded Ryan "for recognizing the looming financial crisis that faces our nation and for the creative and bold thinking that he brings to the debate."
Former Arkansas Gov. Mike Huckabee, who won the 2008 GOP Iowa caucus, applauded Ryan, but noted the proposal has little chance of enactment so long as Democrats control the White House and Senate.
But Ryan's plan has gained so much attention and praise in Republican circles that the contenders won't be able to ignore it for long, if they want to seize control of the debate on their terms.
Candidates who appear tepid about Ryan's cost-cutting might lose favor in primaries dominated by debt-hating conservatives. But heartily embracing the proposals could haunt the eventual nominee if President Barack Obama can portray his challenger as recklessly willing to undercut health care for the poor and elderly.
Dan Schnur, a former aide to Republican presidents and governors, said the contenders are smart to keep their heads down.
"They can't compete for headlines with either the governors or the Republicans in Congress," said Schnur, who heads the Jesse M. Unruh Institute of Politics at the University of Southern California. "So they might as well keep their distance until the dust settles. But at a certain point, those candidates are going to have to engage."
History suggests they be wary of seeking significant changes to Medicare, Social Security or subsidy programs without at least some Democratic support.
One-party drives typically have failed. In 1981 and 1985, President Ronald Reagan and GOP lawmakers unsuccessfully tried to trim Social Security benefits. Gingrich's failed effort to rein in Medicare in 1995 led to politically damaging government shutdowns. President George W. Bush got nowhere with his 2005 bid to partially privatize Social Security, which Democrats denounced.
Happier results came from bipartisan agreements to raise Social Security's eligibility age and payroll taxes in 1983, and to curb welfare benefits in 1996 under President Bill Clinton.
Ryan calls his proposal a cause, not a budget. Such remarks may rally conservatives who say it's time for painful medicine to cure the nation's growing debt habits. GOP presidential candidates will need these voters in the Iowa caucus, New Hampshire primary and beyond.
But by the fall of 2012, Obama may try to convince independent voters that his GOP opponent has embraced a partisan cause rather than a fair, even-handed spending agenda for America.
His allies are laying the groundwork. Ryan's budget "represents the victory of the tea party mentality over mainstream conservatism within the Republican Party," said Bill Galston, an aide in the Clinton White House.
If that message resonates with a wide audience, Ryan's ambitious plan may leave a dubious legacy.