DES MOINES, Iowa (Reuters) — With his Hollywood good looks, huge personal fortune and gold-plated resume, Republican Mitt Romney fits the role of a leading presidential contender.And for the first time, the former governor of Massachusetts is showing some concrete progress in the 2008 race for the White House.

A surprising $21 million first-quarter fundraising haul led all Republican candidates and bankrolled an early advertising blitz, and Romney has surged to a lead in polls in the crucial early voting states of Iowa and New Hampshire.

Romney, who would be the first Mormon to win the White House, still faces doubts about his religion and questions about the sincerity of recent policy switches to oppose abortion rights and gay rights. In national polls, he trails well behind his top rivals, former New York Mayor Rudolph Giuliani and Arizona Sen. John McCain. And he faces a fresh challenge from the race's newest entrant, conservative former Tennessee Sen. Fred Thompson, who runs slightly ahead of him in some polls.

"Welcome Fred, come on in, the water is fine," Romney said of his new rival in an interview during a two-day campaign swing in Iowa, which kicks off the nominating contests.

Romney said he was not worried Thompson would steal his support among the religious and social conservatives he was targeting and who play an influential role in the Republican race.

"We're all going for the same constituency — we're all going for Republicans," he said.

The multimillionaire former venture capitalist said his analytical, results-oriented approach drawn from his experience in business is what Washington needs to solve thorny problems like the Iraq war. While he supported President George W. Bush's decision to go to war and backs his current strategy to increase troops there, he said the United States was "underprepared, underplanned and understaffed" after the fall of Baghdad.

The results of the troop increase in Iraq will be evident by the end of the year <\m> well before the November 2008 election <\m> and failure will require an unspecified "different course of action," he said.

"It's a matter of months, not years, before we get a good read on the level of success," Romney said. "I do not believe we should publish a date for withdrawal in Iraq, but I do believe we should have benchmarks and milestones by which we can assess progress."

In a recent debate, Romney supported doubling the size of the detention camp that holds about 380 foreign terrorist suspects at the Guantanamo Bay Naval Base in Cuba even though it has been a lightning rod for international criticism.

A Saudi prisoner on Wednesday became the camp's fourth apparent suicide since opening in January 2002. "Given the nature of what we face with violent jihad, it would be naive to assume we won't have additional terrorists that are going to be captured, interrogated and not welcome on our soil," Romney said.

Romney, 60, the son of a former Michigan governor and auto executive, was a successful consultant and venture capitalist before rescuing the scandal-ridden Salt Lake City Olympics and serving four years as governor in Massachusetts, one of the country's most liberal states.

He has made ten visits to Iowa this year and nine to New Hampshire, which borders Massachusetts, and he launched a series of ads designed to introduce him in those early voting states.

"Romney is on the move. He won the first two debates and he's buying a boatload of name recognition," said Republican consultant Dan Schnur.

"The more people see him in Iowa, they like him," said Stewart Iverson, a former Senate Republican leader in Iowa and a Romney supporter.

During a day of campaigning in Iowa he got questions about his faith and about his recent switch to opposing abortion rights. He was asked at a West Des Moines campaign event on Wednesday night if he believes all the tenets of Mormonism. "I believe in my faith and I'm proud of my faith," he said. "One of the great things about America is we welcome people of differing faiths and we don't choose our leaders based on which church they belong to."