But a different label applies to his actual record: conservative.
The likely Republican presidential nominee is much more conservative than voters appear to realize. McCain leans to the right on issue after issue, not just on the Iraq war but also on abortion, gay rights, gun control and other issues that matter to his party's social conservatives.
The four-term Arizona senator, a longtime member of the Armed Services Committee, criticized the earlier handling of the war but has been a crucial ally in President Bush's effort to increase and maintain U.S. forces in Iraq.
Besides the war, McCain agrees broadly with Bush and other conservatives on:
_Abortion. McCain promises to appoint judges who, in the mold of Supreme Court Justice Antonin Scalia, are likely to limit the reach of the Roe v. Wade decision that legalized abortion. McCain's record is not spotless on abortion: He said once, in 1999, that Roe v. Wade should not be overturned. But that amounted to a blip in an otherwise unbroken record of opposing abortion rights for women.
"I am pro-life and an advocate for the rights of man everywhere in the world," McCain told the Conservative Political Action Conference in February. "Because to be denied liberty is an offense to nature and nature's Creator."
_Gay rights. McCain opposes gay marriage. True, he does not support a federal ban on gay marriage on grounds the issue traditionally has been decided by states. But McCain worked to ban gay marriage in Arizona. He also supports the military's "don't ask, don't tell" policy, and he opposed legislation to protect gay people from job discrimination or hate crimes.
"I'm proud to have led an effort in my home state to change our state constitution and to protect the sanctity of marriage as between a man and woman," he told CNN in March. "I will continue to advocate for those fundamental principals of our party and our faith."
_Gun control. McCain voted against a ban on assault-style weapons and for shielding gun-makers and dealers from civil suits. He did vote in favor of requiring background checks at gun shows, but in general he sides with the National Rifle Association in favor of gun rights.
When the Supreme Court held arguments last month on Washington, D.C.'s handgun ban, McCain said it was "a landmark case for all Americans who believe, as I do, that the Second Amendment guarantees an individual right to keep and bear arms."
His conservatism could be a problem for McCain _ particularly if this November's contest is as close as recent presidential elections, which were decided by independent-minded voters in the center of the political spectrum.
But he might avoid this problem to the extent people know him as an independent-minded politician. And many do view him that way.
"People see him as a centrist. They don't see him as a conservative," said Andrew Kohut, president of the Pew Research Center for the People and the Press.
"In fact, they put him pretty close to themselves, in terms of ideology, and put President Bush way to the right of themselves," Kohut said.
In a national Pew survey earlier this year, voters placed McCain in the middle, where they placed themselves, when asked to judge the ideology of Bush and the presidential candidates. They placed Hillary Rodham Clinton and Barack Obama far to the left.
And voters who back Clinton and Obama are open to McCain.
Nearly a third of Clinton supporters said they would back McCain if Obama becomes the Democratic nominee, and more than a quarter of Obama supporters said they would back McCain over Clinton, according to Associated Press-Ipsos polling released Thursday.
Democrats are trying to change the perception of McCain. The Democratic National Committee insists that McCain's election would amount to a third term for Bush and Vice President Dick Cheney.
"All he offers is four more years of the failed Bush economy, an endless war in Iraq and shameless hypocrisy on ethics reform," DNC Chairman Howard Dean said last month.
Whatever the general image of McCain, the Christian right is deeply suspicious of him despite his many conservative positions. McCain has clashed with its leaders. He called televangelists Pat Robertson and Jerry Falwell "agents of intolerance" and has often worked against them.
He pushed to limit the influence of money in politics through campaign finance reforms that, critics say, stomp on the constitutional right to free speech.
He backs a path to citizenship for illegal immigrants, which many of his party's most conservative members oppose.
And he splits from the right over research which extracts stem cells from human embryos in an effort to develop treatments for Parkinson's, Alzheimer's and a range of other diseases. Conservatives object because human embryos are destroyed; McCain supports the research.
Polls indicate McCain has the same level of GOP support as Bush had at this point in 2000. But some insist he still isn't reaching out to rank-and-file conservatives who are needed to lick envelopes, make phone calls and knock on doors in states where the election is likely to be close.
On the right and across the political spectrum, McCain's image, rather than his positions on issues, seems to form people's opinion of him. Indeed, in choosing presidents, voters often look past issues to character and personality, and most individual issues are unlikely to mean much.
But one broader issue could figure prominently in November _ the tumbling economy and consequent job losses, home foreclosures and soaring energy prices.
Those could prove troublesome for McCain, and not only because he acknowledges he's no economic expert.
"We are surely in a time of deep economic insecurity for a majority of the American people," said Curtis Gans, director of American University's Center for the Study of the American Electorate. "That has always led to two things: somewhat higher turnout, and votes against the party in power."
"We are also in a deeply unpopular war," Gans said. "Where there are these differences, and strong differences, they could be in the Democrats' direction."