WASHINGTON -- For two days they marched past the huge marble fountain and upstairs to the terra cotta and creamy gold splendor of the grand ballroom at the historic Peabody Hotel in Memphis, Tenn. There, flanked by the flags of more than two dozen states, four U.S. senators who hope to carry the Republican banner in the 2008 presidential election pledged allegiance to one of the GOP's most revered principles: fiscal responsibility -- never spend taxpayers' money you don't have.

Less than a week later, the Senate's Republican majority overwhelmingly approved billions of dollars in deficit spending. And despite cries of outrage from conservative groups that helped build the GOP majorities in both houses of Congress, the Republican spenders were undeterred for one simple reason:

They're convinced that voters care less about big deficits than they do about the things that increased federal spending will buy.

"Senators are betting that pandering to the public with billions in election-year promises will pay off more than they lose by cutting the fiscal conservatives in their own party off at the knees," said Keith Ashdown of Taxpayers for Common Sense.

That political calculation lay behind congressional Republicans' support for creation of the new Medicare prescription drug entitlement in 2003. And it drove Thursday's votes to raise the debt ceiling and approve more deficit spending.

There was another reason many congressional Republicans have turned away from old-fashioned fiscal discipline. Two other elements in the conservative credo, support for greater spending on national security and determination to cut taxes, have left budget makers with so little room to maneuver that significant budget cuts have become extremely hard to make.

Some Republicans warned that the GOP could pay a heavy price for yielding to spending pressures.

Former Rep. Patrick Toomey, R-Pa., who now heads the free-market-oriented Club for Growth, warned that, "Republican voters are going to ask themselves, 'Why bother having Republicans in office?' " Senate Republicans not only have shown "absolutely no semblance of discipline on spending," said Toomey, but they have failed to extend President Bush's expiring tax cuts.

"If they can't do either taxes or spending right, how do they expect Republicans to turn out in the fall to re-elect Republican majorities?" Toomey said. "I think they're in ... for a very rude awakening in November."

"It's a suicide mission," agreed Sen. Tom Coburn, R-Okla. "All this spending has us on a collision course with fiscal disaster." he said. Nonetheless, while he voted consistently against spending proposals this week, in the end he also voted for the final Senate budget with all its added billions.

Democrats, long vilified by their opponents as the tax-and-spend party, think they can turn the tables by calling the Republicans the party of borrow and spend. The federal budget, in surplus when Bush took office in 2001, immediately ran deficits that assumed record proportions.

Rep. John Tanner, D-Tenn., told the House Wednesday that he grew up with three principles: "Live within your means, pay your debts and invest in the future. This government under this leadership is doing none of those."

He noted that on Thursday the House approved a $92 billion so-called "emergency" spending bill that provided $68 billion for the wars in Iraq and Afghanistan and $19 billion for communities struck by Hurricane Katrina. The bill passed handily, 348 to 71, with only 19 Republicans joining 52 Democrats in opposition.

The Senate meanwhile added about $16 billion for a host of domestic programs, including health, education and heating assistance for the poor, to the $2.8 trillion budget for fiscal year 2007 that its Budget Committee had recommended. The budget passed by a scant 51 to 49, with a lone Democrat -- Mary Landrieu of Louisiana -- joining 50 Republicans to form the majority and five Republicans voting no, mostly to protest the budget's call for legislation to open the Arctic National Wildlife Refuge to oil drilling.

"When it comes to fiscal discipline," said Robert L. Bixby, executive director of the Concord Coalition, a budget watchdog group, "the gap between rhetoric and reality on Capitol Hill is as wide as the deficit."

Spending has grown more in Bush's five years in office than it had in President Clinton's eight, even excluding the boom in defense spending under Bush. Altogether, spending rose about 4 percent a year under Clinton and 9 percent a year under Bush.

Despite those numbers, some Republicans think the Democrats will have a hard time persuading the public that they are the party of spending restraint. "It would be even worse under the Democrats," said former House Majority Leader Dick Armey of Texas.

And restraint might have lost some of its political appeal. The Pew Research Center for the People and the Press, in its annual survey in January of what issues weigh on the public, said just 36 percent of conservative Republicans rated the deficit as a "top priority," placing it well below eduction, jobs, terrorism and illegal immigration.

"The deficit," said Carroll Doherty of the Pew center, "does not have the same resonance that it did through much of the 1990s."

Paying homage to fiscal responsibility is apparently still mandatory for Republican politicians who aspire to higher office. Among politicians who vowed to curb spending last week when they addressed a combined meeting of the Southern and Midwestern Republican Leadership Conference in Memphis were four of the party's leading presidential hopefuls: Senate Majority Leader Bill Frist of Tennessee, Sen. John McCain of Arizona, Sen. George Allen of Virginia and Sen. Sam Brownback of Kansas.

All four, however, supported the final budget bill.

Some fiscal conservatives in the House were so furious at the absence of spending cuts to compensate for the extra hurricane relief that they voted against the entire spending bill, including money for the wars.

"I strongly support our troops," said Rep. Jeb Hensarling, R-Texas. "Successfully fighting the war on terror is our most important national priority, but another national priority is saving our children from a mountain of debt or unconscionable tax increases," he said.

For other conservative members of Congress, local interests trumped ideology. Sen. Craig Thomas, R-Wyo., issued a statement Friday praising the Senate vote to make room for another $235 million for rural health care.

"While it is important to identify and eliminate wasteful and inefficient programs," Thomas said, "I also believe that we must support policies that work."