WASHINGTON — Disaffection over spending and immigration have caused conservatives to take flight from President Bush and the Republican Congress at a rapid pace in recent weeks, sending Bush's approval ratings to record lows and presenting a new threat to the GOP's 12-year reign on Capitol Hill, according to White House officials, lawmakers and polling data.

Bush and Congress have suffered a decline in support from almost every part of the conservative coalition over the past year, a trend that has accelerated with alarming implications for Bush's governing strategy.

The Gallup polling organization recorded a 13-percentage-point drop in Republican support for Bush in the past couple of weeks.

These usually reliable voters are telling pollsters and lawmakers they are fed up with what they see as out-of-control spending by Washington and an abandonment of core conservative principles.

There are also significant pockets of conservatives turning on Bush and Congress over their failure to tighten immigration laws, restrict gay marriage and put an end to the Iraq war, as well as the rash of political scandals, according to lawmakers and pollsters.

Bush won two presidential elections by pursuing a political and governing model that was predicated on winning and sustaining the loyal backing of conservatives. The theory, as explained by Bush strategists, is that the president would enjoy a floor below which his support would never fall.

It is now apparent that this floor has weakened dramatically and collapsed in places.

"A lot of us have been like Paul Revere and sounding the alarm for three or four years," said Rep. Tom Feeney, R-Fla.

"Conservatives forgave Bush and Congress for our past mistakes because the war on terrorism was so important ... but now there is a great deal of unhappiness.

"What you are going to increasingly see is a divided Republican Party."

Michael Franc, a top official at the Heritage Foundation, said his organization hosted 600 of its top conservative donors last week and heard more widespread complaining about Republicans than at any point in the past 12 years.

"It begins with spending, extends through immigration and results in a sense that we have Tweedledum and Tweedledee for the two parties," Franc said.

Michael Dimock, of the Pew Research Center, a leading polling group, said one of the most striking findings of recent surveys is the growing number of conservatives who "don't see Bush as one of them [as] they did earlier in his presidency."

Pew found that Bush has suffered a 24-point drop in his approval rating among voters who backed him in 2004: from 92 percent in January 2005 to 68 percent in March.

GOP lawmakers and strategists, who have reviewed a series of polls released in recent weeks, said the results confirm what they are hearing from voters: Conservatives are demoralized and defecting in worrisome numbers.

The most recent Associated Press poll found Bush had a 52 percent approval rating among conservatives; only 33 percent had a favorable opinion of the Republican-run Congress.

"The problem in my mind, and the only way to explain the very significant erosion, is just a disgust with what appears to be a complete abandonment of limited government," said former Republican congressman Patrick Toomey, who runs the conservative Club for Growth.

Since Bush took office, government spending has increased by more than 25 percent, the largest increase under any president since Democrat Lyndon Johnson. At the same time, Bush and the Republican Congress dramatically increased the government's role in — and overall spending on — education and Medicare by enacting the No Child Left Behind law and a new prescription-drug program for seniors.

Karl Rove, Bush's top political adviser, and GOP leaders are well aware of the problem and planning a summer offensive to win back conservatives with a mix of policy fights and warnings of how a Democratic Congress would govern.

The plan includes votes on tax cuts, a constitutional amendment outlawing gay marriage, new abortion restrictions and measures to restrain government spending.

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