"Off-year elections are won through the party's ability to motivate the base and persuade swing voters, and this is good politically from both perspectives," Mehlman said.
The skeptics remain vocal, however. During a visit to the White House this week by Finance Committee Republicans, Sen. Olympia J. Snowe (Maine) told Bush she would be concerned about doing anything that would undermine the guaranteed benefit of Social Security.
"We'll keep you in the open-minded camp," replied the ever-optimistic Bush, according to two people who attended the meeting. Later, she told reporters she will oppose the diversion of payroll taxes to individual accounts, the crux of the president's plan as his aides have discussed it so far.
Fifty-five of the Senate's 100 members are Republicans. Sixty supporters would be needed to overcome a delaying tactic known as a filibuster, so Snowe's voice is critical to the GOP. She said in an interview that it was "clear that he [Bush] was soliciting input, recognizing that it is a volatile and sensitive subject where there are disparate views."
"I always tell my colleagues that the Founding Fathers had a great idea, and that was checks and balances," she said.
The White House got a taste of the legislative branch's coming assertiveness late last year, when two committee chairmen temporarily held up a restructuring of the intelligence services -- which the president said he wanted -- because of concerns about a Bush-backed compromise.
Thomas, the House's chief tax writer and a fearless power broker, used an appearance at a National Journal forum earlier this month to announce that he plans to consider a much broader and deeper review of Social Security than Bush has envisioned.
"You people," he said, gesturing toward several former White House officials, "propose; the Congress disposes." He said Bush's failure to veto any bill so far "means we have some latitude in putting together a package that saves Social Security that is perhaps broader than the theme that he is primarily focusing" on.
That theme is a mechanism to allow younger workers to divert part of their payroll taxes into a personal stock-and-bond account. Thomas wants to use the occasion to consider eliminating the payroll tax and to add a savings program for long-term care. At least some House leaders have hailed Thomas's broadside because they believe that Bush's idea alone would fail but that Thomas's expanded ideas might make the plan more attractive to businesses and older Americans.
Sen. Rick Santorum (R-Pa.), a Bush backer and chairman of a Social Security subcommittee, contends that the differences between Bush's needs and those of the GOP in Congress are not enough to create a real fissure. "It isn't about the president personally anymore," Santorum said. "But at the same time, we all know that if the president's not popular and we're not being successful as a party, it hurts us all."
Sen. Trent Lott (R-Miss.) said the divergence of interests between a White House and a legislative majority of the same party "is natural and happens almost inevitably in a second term."
While the White House thinks Social Security legislation will be dead if it is not signed this year, Sen. John W. Warner (R-Va.) said such an undertaking will take some time, "and it should -- it really should."