Senator John McCain, left, has been a close ally of President Bush’s, but he is positioning himself an opponent of the political establishment.

By PETER BAKER

ST. PAUL - The nominee’s friend described him as a “restless reformer who will clean up Washington.” His defeated rival described him going to the capital to “drain that swamp.” His running mate described their mission as “change, the goal we share.” And that was at the incumbent party’s convention.
After watching two political conclaves recently, it would be easy to be confused about which was really the gathering of the opposition. As Senator John McCain accepted the Republican nomination for president, he and his supporters sounded the call of insurgents seeking to topple the establishment, even though their party heads the establishment.
This was, of course, part Mr. McCain’s nature and part political calculation. It was also part history.
For the first time since 1952, the party holding the White House has nominated someone other than the sitting president or vice president, someone without a vested interest in running on continuity, and at a moment when the party finds it difficult to defend its record from the last eight years.
The effort to position Mr. McCain and the Republicans as the true agents of change benefited from his selection of Governor Sarah Palin of Alaska as his running mate.
Known for taking on her own state party over corruption and wasteful spending, Ms. Palin projects the image of the ultimate Washington outsider, literally from more than 4,500 kilometers outside the Capital Beltway. And she would be the first woman to serve as vice president.
But as a matter of history, it is easier to run as the opposition party if you actually are the opposition party.
“When the president of the United States is from your own party, to present yourself as a change agent is not the easiest thing to pull off,” said Joe Trippi, a Democratic strategist. Referring to Senator Barack Obama, the Democratic nominee, Mr. Trippi added, “All Obama has to do is say, ‘Bush-McCain, Bush-McCain.’”
That was certainly a chant never heard during the Republican convention in the Xcel Energy Center here.
President Bush canceled his trip here to supervise the response to Hurricane Gustav and addressed delegates only by video, before the broadcast networks began their coverage for the night.
Once his image faded from the screen, none of the marquee speakers for the rest of the convention mentioned his name during the nightly prime hour. Indeed, a computer count showed that Democrats mentioned the name Bush 12 times as often at their convention. And delegates were shown a video about the attacks of September 11, 2001, that included a picture of Rudolph W. Giuliani and Donald H. Rumsfeld but none of Mr. Bush . Republicans said Mr. McCain had little choice.
For “every candidate, regardless of whether they’re an incumbent or a challenger,” said Sara Taylor, a former White House political director under Mr. Bush, “one of the fundamental missions is how to set themselves up as the change agent, and John McCain is well equipped based on a long record as a maverick to do that.”
And it is true that even vice presidents running as popular presidents leave office have labored to establish their own identities. “Conventions are always about the next four years, not the last four or eight years,” said Ron Kaufman, who was a top aide to the first President Bush. “In the end, whether your party is in power or not, it’s about, ‘What are you going to do for me for the next four years?’”
Still, even though the elder Mr. Bush wanted to slip out of Ronald Reagan’s shadow in 1988 and Al Gore tried to distance himself from the scandals of Bill Clinton in 2000, they both used their acceptance speeches to boast of their administrations’ records.
By the time the convention here was about to begin, Mr. McCain almost sounded like a speaker at an Obama rally. “I promise you, if you’re sick and tired of the way Washington operates, you only need to be patient for a couple of more months,” he told supporters in O’Fallon, Missouri. “Change is coming! Change is coming! Change is coming!”
Mr. McCain has been a strong supporter of Mr. Bush’s. And the Obama campaign signaled it would not cede the change argument, airing another advertisement showing him with Mr. Bush and concluding: “We can’t afford four more years of the same.”