Sen. John McCain (search), called into action by Vice President Dick Cheney, returned to the site of his greatest political triumph Monday and campaigned for the man who ended his dreams for the White House in 2000 — President Bush.

"I have some disagreements with him, but that doesn't mean that I think his overall record doesn't deserve re-election. I think he does," McCain said after being mobbed by voters while shaking hands in a downtown diner.

McCain upset Bush in the New Hampshire primary four years ago, but lost the GOP nomination after Bush's supporters waged an intensely negative campaign in South Carolina. McCain said he holds no grudge because "the worse thing that anyone in life or politics can do is look back in anger."

"Americans do not like a sore loser," he said. McCain's trip, made after a phone call from Cheney, reflects the White House's concern about leaving unanswered criticism of Bush from the Democrats campaigning in New Hampshire, a swing state in the fall.

McCain took mild jabs at Democratic candidates Wesley Clark (search) and Sen. John Kerry (search) of Massachusetts.

Kerry, who McCain called a friend, has used his tour of duty in Vietnam as a contrast to his opponents who didn't serve. McCain said it's inappropriate politically for candidates to "compare their credentials," because voters will do that.

Later, he said he wasn't criticizing Kerry, only making a political observation.

McCain, a Vietnam prisoner-of-war for more than five years, said he never held it against Kerry for protesting the war after Kerry returned from Vietnam.

"I've never criticized anyone for protesting against the war," McCain said. Noting that Kerry once threw war medals in protest of the war, the Arizona senator said, "I did not approve of throwing of medals, OK? I did not approve of that. But I didn't condemn it. Nor did I ever speak out against it."

Asked if Kerry's actions against the war were relevant to the 2004 campaign, McCain shook his head and said no.

He was tougher on Clark, who recently suggested that Kerry's experience as a Navy lieutenant could not match his own as a four-star general.

"Oh, that just wasn't an intelligent comment," McCain said. "A majority of people who won our nation's highest award have been enlisted people."

He said Clark has made some "equivocal statements," such as wavering on the war in Iraq, and chalked it up to inexperience.

"It's very hard to make the transition from general to politician, so you make mistakes," he said. "I don't think I could go over and become chairman of the Joint Chiefs of Staff or head of NATO, like Clark was."

Asked if the best candidate won the 2000 GOP race, McCain said, "I think if you rely on the judgment of Republican votes, yes."