WASHINGTON - It's hard to imagine now, but there was a time when Senator John McCain was considered a safe bet for the Republican presidential nomination.

Widely admired for a maverick style that seemed to transcend party politics, McCain handily attracted respect and affection as a Vietnam War hero and a straight shooter on bungled policy in Iraq.

Beaten by George W. Bush for the 2000 nomination, it had seemed logical he'd succeed the president in the party's top spot in 2008.

But the aura of inevitability has faded.

He's down in the polls and trailing in fundraising now that his staunch support for the widely unpopular Iraq war has come to define him.

Yet he's pushing the point this week in an all-out bid to re-energize his campaign before formally announcing his candidacy near the end of April.

That means adopting the risky strategy of trying to convince voters that Iraq can be won, bucking the prevailing American mood much as the president and tying his own fate to the war.

Some analysts think he has a chance.

"It's so wide open right now that McCain has the time to turn it around," said Patrick Basham, director of the conservative Democracy Institute think-tank.

"His best hope is that no one can fill the vacuum as the new (Ronald) Reagan" - the popular late president who's still regarded by Republicans as a conservative giant.

Still, it's going to be far from easy. And last week was a spectacularly lousy one.

The Arizona senator's fundraising total for the first quarter of 2007 came in at US$12.5 million, respectable but well behind former Massachusetts Gov. Mitt Romney at $23 million.

Republican front-runner Rudy Giuliani, the former New York mayor, had $15 million.

The three top Democratic contenders, Hillary Clinton, Barack Obama and John Edwards, also raised more than McCain.

He compounded his problems by taking a tour of a Baghdad market in a bullet-proof vest and pronouncing it safer than ever while surrounded by dozens of soldiers with helicopters flying overhead.

"Never have I been able to go out into the city as I was today," he said, a comment that sparked derisive headlines about his judgment.

The TV appearance was widely dubbed the "photo-op from hell."

"There are neighbourhoods in Baghdad where you and I could walk today," he insisted before leaving on the trip.

McCain, 70, started his offensive Sunday with an editorial in the Washington Post and a television interview where he defended his optimism and blamed media organizations for ignoring positive developments.

He was candid about bucking the tide of American anger over Iraq and attempts by Congress to impose a deadline for withdrawal.

"I disagree with what the majority of the American people want. Failure will lead to chaos, withdrawal will lead to chaos."

He took the same tack Monday at a news conference in Phoenix.

"We are making some progress but it will be long and difficult. Unfortunately, the American people are not being told about the progress being made. They should be."

And he defended his characterization of Baghdad's safety.

"Two months ago, there was a huge bombing in that very same place that I was, where about 200 people were killed. That place is being rebuilt today and is a functioning market. Of course, it isn't entirely safe, but it certainly is a functioning market and progress is being made there."

Aides say a major speech Wednesday on Iraq will praise the progress made by the new top U.S. commander in Iraq, Army Gen. David Petraeus, although McCain would like to see many more extra soldiers in Iraq than Bush is providing in his surge plan.

It seems to many that McCain, who has 20 years in Congress, has strayed a long way from the blunt, independent, honest image that made him so popular - the Republican who was unafraid to take Bush on early over problems in Iraq.

And he's facing skeptical party members who still remember his criticism of evangelical leaders in 2000 and don't like the fact that he's championed campaign finance reform and strong measures to combat global warming.

In Giuliani, there's another more recent hero who guided New York City through its worse crisis after the terrorist attacks in 2001.

But the party's still clearly casting about for an heir apparent, opening the door for another contender like former House Speaker Newt Gingrich or actor Fred Thompson, a former Tennessee senator who now appears on the show Law and Order.

Meantime Tommy Thomspon, who was once Bush's health secretary, said he was the "reliable conservative" voters want when he jumped into the race last week.

Beyond Iraq, McCain is facing questions about his age. He'll be 72 next year and would be the oldest first-term president if he won.