Republican congressional leaders say they are standing behind President Bush's proposal to remake Social Security (search) but concede they may not be able to win congressional approval of it this year.

"This is the mother of all issues," House Majority Leader Tom DeLay (search) said Tuesday.

He added that opponents of the president's plans "are better organized than we are."

DeLay, Senate Majority Leader Bill Frist (search) and numerous other GOP lawmakers said Bush's public campaigning has begun to show results, but that more work lies ahead to build support for personal investment accounts as part of a program to make Social Security solvent for the long term.

"People have bought into the fact that we have a problem" with Social Security's future financing, said Sen. Johnny Isakson of Georgia.

"The president will have to stay out there and lead on it, when a lot of political figures want to run and hide and when you have a lot of people who say there's no problem," said Frist.

Republican leaders began surveying their rank-and-file after a weeklong absence from the Capitol as Senate Democratic Leader Harry Reid offered his own blunt assessment of the Bush's signature issue. "I don't think the Republicans are very happy about the position the president is putting them in," he said.

"In two months, the president has created a firestorm against" his own plan, said Sen. Chuck Schumer, D-N.Y.

Bush is to travel to six states over the next two weeks, and many more later as he tries to build public support for an overhaul of the Depression-era government program.

Echoing White House claims, congressional Republicans said they hope that by the time he is finished, the president will have produced a public groundswell for legislation, forcing at least some Democrats to reconsider their opposition.

"My goal is to have it on the floor" this year, Frist said. "I want to be realistic and make sure we can have a bill that can be debated and move through this body."

DeLay told reporters there is enough time to complete work on Social Security this year. Later, though, he was less than definitive on the prospects. "I hope so," he said when asked whether legislation can pass this year. "We're shooting to get it done this year."

Bush has said his plan would guarantee that Social Security benefits would remain unchanged for retirees and workers age 55 and over. Younger Americans would be allowed to invest a portion of their payroll taxes on their own. In exchange they would receive a lower government benefit than they are now guaranteed, on the assumption that the proceeds of their investments would make up the difference.

One senior Republican said some of his colleagues were devoting too much attention to day-to-day movement in public polls.

"As far as I'm concerned, I'm going to wait another month before I take a poll seriously," said Charles Grassley, R-Iowa, chairman of the Senate Finance Committee (search).

Grassley said he intends to hold hearings in April in his panel on the issue, and use the intervening weeks to better inform Republican members on the intricacies of the program.

But he said, "I don't have a timetable" when it comes to making decisions on what to include in any legislation, or on when to bring it before his panel. He said earlier this year Bush had 90 days to make his case.

Officials have long said the Senate is likely to go first in considering any Social Security legislation.

Republicans have firmer control over proceedings on the House floor, but rank-and-file lawmakers there are not eager to take a series of politically difficult votes on Social Security if the measure is to run aground in the Senate.

A few GOP House members from competitive districts said their experiences in town hall meetings last week left them willing to follow Bush's lead.

"We have to find a way to strengthen Social Security so my personal hope is we can keep moving forward toward reform," said Rep. Chris Chocola of Indiana. He said he held seven meetings with his constituents last week, encountered large audiences and found them generally receptive as he outlined the financial difficulty facing the program. Still, he said "the politics are a challenge," an acknowledgment that Democrats hope to make an issue of Social Security in the 2006 elections.

Rep. Rick Renzi of Arizona, whose district is home to large numbers of retirees, said his audiences seemed receptive, and told him they want Social Security to be available for their children. "What I'm seeing among our elders is a real charity and generosity," he said.