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President Bush has pledged to pursue changing Social Security (search) until his final day in office, but the challenge he faces was evident Thursday. He stumped for his program in the district of an undecided House Republican who was traveling overseas.

"I'm spending a lot of time convincing seniors nothing changes, and convincing folks there's a problem," Bush said, making his 33rd campaign-style appearance on Social Security since declaring it his top domestic priority in February.

"Because once the people realize the problem, then the next question they ask to their elected representative is, 'We've got a problem ... so what are you going to do about it?"' he said.

People in the hand-picked audience applauded, but their congressman, Rep. Ed Whitfield (search), R-Ky., was away on a previously scheduled government trip to Cyprus and Turkey. His parents stood in for him, sitting in a pair of front-row seats.

Whitfield's absence underscored the tepid support some Republicans feel for the principal White House proposals: allowing workers under age 55 to establish investment accounts with a portion of their Social Security payroll taxes, and retooling how future benefits are calculated so that checks for all but the lowest-wage workers grow more slowly.

"I think one thing that he does believe is that, yes, Social Security is a problem, but we also have big financial problems with Medicare (search) and Medicaid, which are also deserving of focus," Whitfield's legislative director, John Halliwell, said of his boss.

Medicare, the federal health program for the elderly, faces a projected shortfall of $28 trillion over the next 75 years, seven times worse than the $4 trillion projected shortfall for Social Security, the federal retirement and insurance program for survivors and the disabled.

"The congressman has said publicly he supports the concept of personal accounts, but he has not committed to any one proposal," Halliwell said. Both of the state's senators, Republicans Mitch McConnell (search) and Jim Bunning (search), support the accounts proposal, with Bunning labeling them "a life preserver to save Social Security."

In Whitfield's western Kentucky district, nearly 10,000 people receive monthly Social Security checks. The president pivoted off the rural setting in Christian County to argue that his overhaul would help farmers, one of whom joined in a panel discussion he moderated.

"Congress has got to understand that if you've got a 29-year-old farmer working hard, putting money into the system, sitting right up here in front of all these cameras saying, 'I'm no so sure the system's going to be there for me,' that's the problem," Bush said. "And that's the problem that I'm going to spend whatever time is necessary talking about, to get the folks up there to get something on behalf of this good man."

Nonetheless, the White House had expected to be beyond this point by now.

The president spent March and April on an aggressive tour highlighting the urgency of the program's finances. Democrats have opposed the account proposal in rare unison, arguing that it undercut the program's ability to continue providing a guaranteed check by diverting its funding into the private accounts.

That concern appears to be shared by some Republicans such as Whitfield, prompting Bush to visit their districts and make his case directly to their constituents. Last week the president visited the district of Rep. Tom Reynolds, R-N.Y.

At the same time, the president is trying to downplay expectations.

"This is just the beginning of a very difficult debate," he told reporters during a news conference Tuesday. While Bush said he expected an eventual breakthrough "like water through a rock," he added again, "We're just beginning the process."

Bush then traveled to St. Louis for a $2,000-a-plate GOP fundraiser that brought in more than $1 million for Sen. Jim Talent, R-Mo., who faces re-election next year. The president urged Talent's colleagues in the Senate to confirm his nominee for U.N. ambassador, John Bolton.

"It's time for the United States to stop playing pure politics — stall politics — and give John Bolton an up-or-down on the Senate floor," Bush said. "People look at the government and say, 'What's going on with all this stuff — filibustering? Why can't people come together and do what's right for the country?"'

A vote on Bolton's nomination was held up by Senate Democrats last week because of a dispute over documents they claim the White House has refused to provide. Congress returns from its Memorial Day recess next week, which further delays a vote on Bolton, who has been criticized for his views on international relations and his treatment of subordinates.