A former governor of Massachusetts, Mitt Romney yesterday became the first of the leading Republican hopefuls to make official his bid for the 2008 presidential nomination, casting himself as an outsider who can transform the government.

Mr. Romney, 59, chose his native Michigan, a presidential election battleground, as the setting for the announcement. Mr. Romney was born in Detroit and his father, George Romney, served as Michigan governor between 1963 and 1969.

“I do not believe Washington can be transformed from within by a lifelong politician,” Mr. Romney said at the Henry Ford Museum in Dearborn. “There have been too many deals, too many favors, too many entanglements, and too little real world experience managing, guiding, leading.”

Mr. Romney has reached the top rung of Republican contenders in the past year by aggressively building a national campaign network, hiring top political talent, and raising millions of dollars a year before the first contests in the nomination race.

That has helped put him in the hunt with the two most prominent Republicans considering a run, Mayor Giuliani and Senator McCain of Arizona, both of whom have national reputations and high profile perches from which to conduct their campaigns.

“The fact that Romney has broken into that first tier is no small feat,” said Scott Reed, a Republican political consultant who ran the 1996 presidential campaign of a former senator, Bob Dole.

From Dearborn, Mr. Romney plans visits to Iowa, New Hampshire, and South Carolina, three states that that will hold some of the first votes leading to selection of the Republican and Democratic nominees for president.

Mr. Romney’s single term as governor of Massachusetts and previous experience as an executive, including overseeing the 2002 Winter Olympics in Salt Lake City, give him a record to sell to voters. The record also gives critics a point of attack.

He won attention for overhauling health care in the state, requiring everyone to have health insurance, whether through employers, Medicaid or as part of a pool for lower-income residents. Mr. Romney also balanced the Massachusetts budget without raising income or sales taxes and is credited with improving the state’s school test scores in math and science.

Governors also have a good track record in presidential races: Four of the last five presidents served as state chief executives.

Mr. Romney, who is the former chairman of Boston-based management- consulting firm Bain & Co., also may benefit from contacts he made in business.

“That’s a very good niche for him to work,” said Steffen Schmidt, a political science professor at Iowa State University. “They are people who are not on the front end of politics but they can be very helpful” with fund-raising, he said. Days after forming his exploratory committee, Mr. Romney brought in $6.5 million in a single day.

Mr. Romney chose the museum as a backdrop to buttress his campaign theme of “innovating and transforming” business and government. “Talk is easy, talk is cheap,” he said. “It is doing that is hard.”

Touching on traditional Republican themes, Mr. Romney said the nation is “overtaxed and government is overfed” and promised to work to strengthen American families. On homeland security, he stressed the importance of secure borders.

Mr. Romney reiterated his support for sending more troops to Iraq, a position also backed by Mr. McCain and one that has drawn fire from war critics in both parties. “So long as there is a reasonable prospect of success, our wisest course is to seek stability in Iraq, with additional troops endeavoring to secure the civilian population,” Mr. Romney said.

Given the competition, Mr. Romney must make his appeal to Republican social, religious and economic conservatives to win, said David Rohde, a Duke University political science professor.

“He can’t contest the maverick or moderate segment of the party,” said Mr. Rohde. Those voters likely will be drawn to Mr. McCain, who has publicly opposed President Bush on issues from tax cuts to campaign finance reform, or Mr. Giuliani, who supports abortion rights, stem-cell research, and gay rights.

Mr. Romney’s “challenge is to become, if not the candidate of the base, at least the candidate who is more appealing than the other players,” said Mr. Rohde. “That’s a hard challenge partly because of his history and partly because of his religion.”

The history is his changing stances on two issues important to core Republican voters.

In an unsuccessful 1994 bid for the Senate in Massachusetts, a strongly Democratic-leaning state, Mr. Romney supported a woman’s right to an abortion and criticized his party for not giving gay men and women more support. He told Bay Windows, a Boston gay newspaper, that he would be a better advocate for homosexuals than the incumbent, Senator Kennedy, a Democrat.

He took similar stances in his 2002 gubernatorial election.

Mr. Romney now says he is firmly anti-abortion and has been an advocate for a constitutional amendment banning same-sex marriage, aligning him more with Republican conservatives.

“Once you get tagged as a flipflopper in national politics it’s very difficult to get back,” Mr. Reed said.

Mr. Romney’s Mormon faith may be an obstacle to winning over evangelical Christians, who have a strong voice the party and some of whom regard Mormonism as a cult. A July Bloomberg/Los Angeles Times poll found 35% of registered voters say they wouldn’t vote for a Mormon for president. That includes about a third of both Republicans and independents.

Facing questions about his positions early in the race may work to Mr. Romney’s benefit, said Peverill Squire, a political science professor at the University of Iowa. “It gives him an opportunity to respond and an opportunity to continue to try to reinforce the notion that he is a true conservative,” Mr. Squire said.

The biggest obstacles for Mr. Romney now are Messrs. McCain and Giuliani. In Iowa, where Republicans will vote in caucuses next January, Mr. Giuliani is preferred by 27% of likely voters and McCain gets 22%, according to a January 29–February 1 American Research Group poll. Mr. Romney trails with 11%, behind a former House speaker, Newt Gingrich, who hasn’t formed a campaign.

Mr. Romney does better in New Hampshire, which borders Massachusetts, drawing 20% of the vote in the ARG poll, tying Mr. Giuliani behind Mr. McCain’s 27%.

Mr. Romney will need to gain traction fast if he is to have any chance of besting the two leaders, said Julian Zelizer, a professor of history and politics expert at Boston University. Mr. Romney “really has to show … he can actually defeat John McCain.”