MANCHESTER, N.H. (AP) — Former Utah Gov. Jon Huntsman is joining the fast-growing pack of Republicans battling to take on President Barack Obama.

Huntsman, who was Obama’s ambassador to China until a month ago, will make his formal announcement next Tuesday — with the Statue of Liberty as the backdrop, his campaign team said. Though he served in Washington for three Republican presidents, he faces a challenge in making himself known nationally and winning over GOP primary voters.

Still, the fact that he’s entering the race shows the turmoil that still fills the Republican field as time ticks down to the first 2012 primaries and caucuses.

Other GOP candidates were hard at it on Tuesday after their first big debate the night before in New Hampshire, keeping up their verbal pounding of Obama.

Front-runner Mitt Romney campaigned at a family-owned hardware story in Derry and declared, “You can’t blame George Bush anymore. President Obama is going to have to take responsibility for the fact that we’re still in a very troubled economy.”

His competitors had hoped the debate would deflate the air of inevitability the former Massachusetts governor has projected in his second White House run. But that didn’t seem to happen.

Minnesota Rep. Michele Bachmann announced her candidacy at the debate and briefly claimed the spotlight, but then she had to return to her job in Washington.

Former Minnesota Gov. Tim Pawlenty had to be goaded to repeat his criticism of Romney’s health care plan as “Obamneycare,” a term he coined conflating Obama and Romney’s health care records.

“It’s a term I used on a Sunday morning show to make the point that President Obama admitted that he used the Massachusetts health care plan as the blueprint for Obamacare,” Pawlenty told CBS News. “And then when pressed by the moderator, I did use that term again.”

And former House Speaker Newt Gingrich, stopping by a breakfast for small businesses, tried to keep the focus on Obama and his stewardship of the economy — not his own faltering campaign or his fellow Republicans.

“I think the American people are hungry for somebody to explain how to end the Obama depression,” said Gingrich, whose top aides resigned en masse last week in a disagreement with the former Georgia lawmaker.

Huntsman, meanwhile is just getting under way.

“I intend to announce my candidacy for the presidency of the United States of America a week from today,” he said during a discussion about China policy in New York with former Secretary of State Henry Kissinger.

His campaign will begin in earnest at the northern New Jersey park where President Ronald Reagan began his 1980 White House run, according to advisers who noted that he had worked as a staff assistant in the Reagan White House. From the Statue of Liberty, Huntsman plans to travel to New Hampshire, the first-in-the-nation primary state, and to Florida, a perennial battleground and host of the 2012 GOP nominating convention. He also plans stops in his home state of Utah and in the early caucus state of Nevada.

Though he’s a two-term governor from a conservative state, Huntsman’s moderate stances on some issues and service as Obama’s ambassador to China could hurt him with the Republican Party’s right-leaning base. He has honed a message of service to his country and has called for civil political discourse.

In a field lacking deep foreign policy credentials, Huntsman is pitching himself as a politician with international experience who would help the United States’ economy rebound. It’s an attempt to appeal to segments of the GOP that care both about foreign policy and domestic prosperity.

The telegenic former governor has a ready fundraising apparatus. He’s personally wealthy and could dip into that fortune for a run. He also has strong ties to the Mormon community, which has shown a willingness to support politicians who are of the faith.

Still, Huntsman’s challenges are great.

For one, he’s simply not well-known. He ranks in the single digits in early national polls as well as in surveys in early nominating states. But many GOP primary voters are undecided, and many conservatives are looking for an alternative to Romney, the former Massachusetts governor and fellow Mormon who is making his second bid for the GOP nomination.

While Huntsman’s record on abortion and gun rights is solidly conservative, his positions on climate change and civil unions for same-sex couples are not. As governor, he backed bills providing civil rights protections to gays and lesbians, and he has said humans have had a role in climate change.

And in 2008 Romney couldn’t persuade evangelical voters who are influential in primaries in Iowa and South Carolina to overlook their skepticism about a Mormon candidate.

Huntsman already has said he would bypass Iowa, which holds the lead-off caucuses in February 2012. Instead, his campaign would begin in New Hampshire, where independent voters can cast ballots in either party’s primary and are the state’s largest political bloc.

From here, Huntsman would compete in South Carolina and Florida in hopes of building momentum.

He long had been considered a potential challenger to Obama in 2012, but then the president offered Huntsman, a speaker of Mandarin, the China job in 2009. At the time, the White House was credited by some with vanquishing a GOP rival.

But a year later, Huntsman bought a $3.6 million Washington mansion that most recently housed contestants on Bravo’s “Top Chef” reality show, and he hinted at national aspirations in interviews. By winter, Huntsman had submitted his resignation, which took effect this spring.

He’s also proved a skilled, folksy-when-needed politician. During one stop at a New Hampshire gun store, he seemed to take a swipe at Romney. Asked what he hunted, he said, “Varmint.”

During the 2008 campaign, Romney said he was a lifelong hunter, but aides said he had been hunting on only two occasions. Romney later said he had hunted more than twice but only for “small varmints” and that he did not own a gun or have a hunting license.

On Tuesday, Romney was smiling. He held an impromptu and atypical news conference outside a farm store and brought reporters along as he went table-to-table in a diner.

“Five years ago it was, ‘Who the heck or you?'” Romney said. “Now it’s, like: ‘Oh yeah, I know who you are.’ Either, ‘I know who you are, please leave my table’ or, ‘I know who you are, I’m going to vote for you.’ I like the latter a lot better.”

Projecting confidence, he promised one storeowner he would be back in four years: “Only next time, it will be a larger group. I will probably have Secret Service.”

Gingrich is trying to reboot a political operation that now has shed top operatives who said they had seen enough to know his strategy of online efforts and sporadic events was not going to win him the nomination.

He seemed to shift that strategy slightly. Two weeks ago, Gingrich attended what his campaign billed as a town hall-style meeting that lasted just 15 minutes and skipped past the traditional back-and-forth exchanges with voters. On Tuesday, he offered brief remarks but spent more than 30 minutes in the hallmark question-and-answer time.

In both cases, Gingrich refused to talk with reporters. “Cover the speech. Cover the speech,” he said.

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Associated Press writer Beth Fouhy in New York contributed to this report.