April 20 (Bloomberg) -- Forget about whether Senator John McCain is a maverick or a mainstream Republican, whether he has moved to the left or right, or whether he has changed his positions in order to prepare for a presidential run in 2008.

The real barrier to his ambitions may be his unswerving, unstinting and unnuanced support for an unpopular war in Iraq.

``I do understand it could be a political liability,'' the 69-year-old Arizona senator said in an interview. While he said he is ``a bit resentful'' of Defense Secretary Donald Rumsfeld ``for the way the war has been poorly handled,'' McCain added, ``I still think we've got to win the war.''

With only 38 percent of Americans in the Bloomberg/Los Angeles Times poll saying the war is worth fighting, McCain's advisers are trying to make a virtue of his stance, saying it shows he is genuine, courageous and un-political. When 2004 Democratic presidential candidate John Kerry ``attempted to be `adroit' about the war, the public didn't like it,'' said John Weaver, McCain's chief political strategist. ``McCain is a straight shooter.''

At the same time, Weaver acknowledged the potential political damage. ``It is stay-the-course, no matter what. And if it dooms McCain, so be it,'' he said.

Ignoring War Cost

Support for the war holds another pitfall for McCain. One of his big selling points is that he is a fiscal conservative committed to cutting wasteful spending. As he travels around the country, in almost every speech he criticizes Congress for appropriating $233 million for a ``bridge to nowhere'' in Alaska and ``$3 million to study bear DNA in Montana.'' Yet he never mentions the more than $250 billion the Iraq war has cost U.S. taxpayers so far.

``There has been huge waste and corruption in Iraq,'' McCain acknowledged, ``and we are paying for those mistakes we made early on: the failure to control the situation, the failure to stop looting, the failure to co-opt people, and mostly not having enough troops. In the next six months, I believe we will see significant progress or you are going to see it go the other way.''

Support for the war also may sap his strength on a signature party issue, the senator conceded. ``Traditionally, the issue of national security helps Republicans,'' said. ``But that erodes as support for Iraq erodes.''

While McCain says he will make up his mind about running sometime after the November elections this year, his political team is already laying the groundwork and, most importantly, buttonholing political donors.

Need to Prepare

``It would be malpractice not to prepare for a potential presidential candidacy,'' Weaver said. ``We need to talk to the grassroots and the people who can fund a 50-state campaign.''

Unlike New York Senator Hillary Clinton, who has raised almost $20 million for her re-election campaign this year and who can use any unspent money for a presidential bid, McCain has only about $1 million sitting in his senatorial kitty. Weaver expects the 2008 primaries to be very expensive and one measure of who wins and who loses ``will be do you have a relationship with people and a structure to quickly raise money?''

Dan Schnur, who was McCain's director of communications in 2000 and isn't working for him now, said McCain would face a tougher challenge this time than he did in his 2000 presidential bid. ``Unlike last time, there is no way for him to sneak up on anybody,'' Schnur said. ``Last time, we had the better part of a year 'off-Broadway' before the spotlights came on. There's a lot less margin of error when everybody is paying attention from beginning.''

Change on Falwell

McCain has already been hit hard recently by a number of critics for forsaking his ``maverick'' principles to woo the more conservative Republican mainstream. McCain, who once denounced religious leader Jerry Falwell as an ``agent of intolerance,'' today says let bygones be bygones and has agreed to speak at Falwell's university. And McCain, who once opposed Bush's tax cuts, today supports their continuation.

To those who say he is selling out to position himself for a presidential run, McCain points to his support for climate change legislation, immigration reform, and a ban against torture. ``These are not popular with my party,'' he says.

Schnur says some criticism of McCain today comes from an idealized memory of him in his first bid. ``There are a lot of people who look back at the 2000 campaign through rose-colored glasses,'' Schnur said. ``On the one hand, it was a magical, transformative experience. On the other hand, it was a commonplace, mediocre campaign.''

Beating Hillary

Tom Rath, the Republican National Committeeman from New Hampshire, says the party race will get down to McCain, Governor Mitt Romney of Massachusetts and Senator George Allen of Virginia. ``What would help McCain the most? -- A whole bunch of polls showing him beating Hillary,'' Rath said.

McCain's advisers are trying to sell the notion that he's the most electable Republican and that he can put California in play in the general election. California, which has a fifth of the electoral votes needed to win the presidency, hasn't voted for a Republican for president since George H.W. Bush carried the state in 1988. Even if McCain couldn't win the state, the argument goes, he would force his Democratic opponent to spend extra time and money there.

``I would say that absolutely McCain could put California in play,'' said Duf Sundheim, chairman of the California Republican Party. ``Of the major people being talked about, I see he has tremendous cross-over appeal.''

Romney and Allen are also favorably received when they visit California and former New York Mayor Rudy Giuliani would be popular in the state should he decide to run, Sundheim said.

Somber Times

McCain concluded a seven-day, six-state tour last weekend, including visits to the politically important states of New Hampshire and Iowa. But he wasn't the rollicking campaigner of six years ago, appearing largely subdued and almost somber at times.

``We live in sober times,'' Weaver said. ``We face incredible international tensions and have domestic issues that are very serious despite a good economy.''

McCain says he has no lack of enthusiasm and still gets fired up while campaigning. ``The passion and enthusiasm must be there or it is a guaranteed loss,'' he said.

Last Updated: April 20, 2006 00:04 EDT