"I realize it's an uphill battle - I'm the underdog in this race," McCain said aboard his campaign bus as it wended its way from Allentown to Pipersville in Upper Bucks County, where he was holding a town-hall meeting.

"We've got to get on this bus and go across Pennsylvania to the small towns . . . [and] we have to convince people that I have a plan of action to fix the enormous economic challenges and problems they're facing," McCain said during his one-day visit to the state. "I have a lot of work to do."

Dominating the campaign yesterday, though, was the fallout from Sunday's remarks about McCain's military experience by Gen. Wesley Clark, a supporter of Democratic Sen. Barack Obama. Clark said that McCain, a Navy pilot who was shot down and held prisoner for five years in Vietnam, never held a major command and thus his military experience was irrelevant to his qualifications for the presidency.

Obama was forced to detour from a speech in Independence, Mo., defending his own patriotism to repudiate the remarks, which Clark made on CBS's Face the Nation.

Patriotism "must, if it is to mean anything, involve the willingness to sacrifice," Obama said. "For those like John McCain who have endured physical torment in service to our country - no further proof of such sacrifice is necessary."

To loud applause, Obama said: "Let me also add that no one should ever devalue that service, especially for the sake of a political campaign, and that goes for supporters on both sides."

Speaking aboard his bus, McCain said he accepted Obama's repudiation of Clark but added that the entire episode illustrated what he called a pattern of personal attacks through surrogates by the Democrat's campaign.

"The beat goes on . . . ," McCain said. "It's quite remarkable, but that's what the Obama campaign has been doing for a long period of time. Fine – but then don't turn around and say we're going to have a different kind of politics. This is politics as usual."

McCain said Obama surrogates had also, in his view, unfairly blamed former Sen. Phil Gramm (R., Texas) for banking deregulation that some say contributed to the subprime mortgage-lending crisis. The McCain campaign also unveiled a "truth squad" of former military leaders to respond to attacks on the candidate's record.

"This debate doesn't decrease the price of oil by 1 percent, doesn't hire one worker, or keep a single family from losing their home," McCain said.

McCain spoke as he was heading into territory that is complicating his task, the Philadelphia suburbs, which have been voting Democratic in presidential races since 1992 and where, in some counties, the GOP has lost its longtime edge in voter registration.

Democrats now outnumber Republicans in Bucks County, for instance, by 6,620 registered voters.

McCain said that the GOP had lost its edge in the suburbs because "we dispirited our base" by letting government spending get out of control and because of corruption cases involving congressional Republicans, including that of convicted former lobbyist Jack Abramoff.

McCain's analysis differs from the consensus among pollsters that the national party's dominance in recent years by social conservatives has turned off the more moderate suburban voters that used to be the party's mainstay.

McCain also said he wears his support for continuing the war in Iraq as a badge of honor, despite evidence that the war's unpopularity is weighing on his party's electoral prospects.

The surge in troops he championed is working, McCain told about 1,200 people who packed a warehouse at Worth & Company, which makes heating and air-conditioning equipment.

"That success is fragile," he said during the 40-minute town-hall event. "If we continue this kind of strategy and success, Americans will come home in victory and honor and not in defeat."

McCain also fielded questions on subjects ranging from energy independence to immigration to autism.

Last night, McCain was scheduled to attend a fund-raiser in Bryn Mawr at the home of Mitchell Morgan, a real-estate investor. Organizers said the event was expected to raise at least $1 million for McCain and the Republican National Committee.

See more from the campaign trail via http://go.philly.com/pavotes08