MANCHESTER, N.H. — Mitt Romney’s Republican presidential rivals repeatedly attacked him as a candidate of the status quo and a timid, less-than-reliable conservative Thursday as they simultaneously sought to slow his campaign momentum and personally audition for the role of conservative rival-in-chief.

“Don’t settle for less than America needs,” said Rick Santorum, eager to capitalize on his second-place finish behind the former Massachusetts governor in this week’s Iowa caucuses, a scant eight votes off the pace.

A heavy favorite to win New Hampshire’s primary next Tuesday, Romney all but ignored his Republican rivals as he campaigned in two states. Instead, he criticized President Barack Obama as a “crony capitalist. He’s a job killer.”

Without saying so, the rest of the field appeared to share a common campaign objective — hold down Romney’s vote totals in New Hampshire, then knock him off stride 11 days later in South Carolina, the first Southern primary of the year.

Romney benefited handsomely from having several rivals split the vote in Iowa, where his winner’s share was roughly 25 percent.

“Gradually you are going to see we have a difference of opinion about which will be the last conservative standing,” former House Speaker Newt Gingrich told reporters as he campaigned in New Hampshire. “But I think you’ll eventually come down to one conservative and Gov. Romney and he’ll continue to get 25 percent.”

Also vying to emerge as Romney’s chief rival were Texas Rep. Ron Paul and former Utah Gov. Jon Huntsman, while Texas Gov. Rick Perry awaited South Carolina.

“We can’t afford to have a status quo president,” Huntsman said in Durham, N.H. “We can’t afford to have a coronation for president.”

Huntsman made hay out of winning the endorsement of The Boston Globe. It was the second time Massachusetts’ largest newspaper had snubbed Romney ahead of the New Hampshire primary.

Gingrich unveiled a new television commercial aimed at voters in New Hampshire and South Carolina that cited one review of Romney’s jobs program as timid and nearly identical in part to the president’s.

“Timid won’t create jobs. And timid certainly won’t defeat Barack Obama,” the ad said.

Ironically, in a year in which polls show the economy is overwhelmingly the top issue for voters, the first two contests are in states with low joblessness — 5.7 percent in Iowa and 5.4 percent in New Hampshire.

That all changes a week later.

South Carolina’s unemployment was 9.9 percent in November, according to the Bureau of Labor Statistics, worse than 41 other states and more than a full percentage point higher than the national average.

Santorum, a former Pennsylvania senator, managed to criticize Romney and most of the other Republicans in the race in the space of a few sentences.

“I’ve never been for government-run health care,” he said in a swipe at both Romney and Gingrich. “I’m not for no regulation, I’m not a libertarian,” he added, a jab at Paul.

Yet he also fielded pointed questions from his audiences — something that he said happened regularly in Iowa, when he campaigned with little or no media coverage for months.

In Tilton, N.H., he was pressed for his views on gun control, given his endorsement in an earlier campaign for former Pennsylvania Sen. Arlen Specter, who favored restrictions. Santorum responded that he is committed to the rights of gun owners.

Later, in an appearance before college students in Concord, he was asked about his opposition to same-sex marriage, which is legal in New Hampshire. “So anyone can marry anyone else?” Santorum said, swiftly turning the conversation to polygamy. “So anyone can marry several people?”

The crowd objected and tried to talk over him.

“Stop. This is not participatory. We’re not going to do this. I’m going to ask the question,” Santorum said, growing testy.

Santorum’s aides say he has raised $2 million on the strength of his Iowa showing. The campaign sought to show momentum by announcing the support of a New Hampshire tea party leader and Catholicvote.org, an online organization, as well as another state senator and the chair of the conservative think tank Cornerstone.

“Our mission here is to show that we’re the conservative alternative to Mitt Romney,” Santorum said, virtually conceding he wouldn’t be able to close a yawning New Hampshire gap in the polls before next Tuesday.

Gingrich sought to set a high bar for Romney. “It’s probably one of his three best states, but we’ll see whether he gets a majority here,” he said.

In the ebb and flow of the campaign, one-time national front-runner Gingrich was hoping to reverse a slide that landed him in fourth place in Iowa. Santorum is ascendant, and Huntsman is hoping to make a statement after skipping Iowa to concentrate on New Hampshire.

Paul, somewhat curiously, was absent, after a third-place finish in Iowa. He is scheduled to arrive in New Hampshire on Friday, in time to campaign and participate in a pair of weekend debates.

Perry, who finished fifth in Iowa, is bypassing New Hampshire to try and resurrect his chances in South Carolina.

Minnesota Rep. Michele Bachmann dropped out after a last-place showing in Iowa, and her erstwhile rivals quickly contacted her supporters in South Carolina, hoping to enlist them in a new cause.

Her campaign manager there, state Sen. Lee Bright, said he has been contacted by aides to Huntsman and Santorum but intends to remain neutral for the time being.

Romney’s strengths in New Hampshire include a familiarity that comes with having served as governor of next-door Massachusetts for four years. He also campaigned in the state in 2008, when he made his first run for the White House.

A relative newcomer on the national stage then, he lost to Sen. John McCain, who won the GOP nomination.

Now, four years later, McCain is campaigning for him, as is South Carolina Gov. Nikki Haley.

In a television ad launched in South Carolina, Romney criticized the Obama administration for bypassing the Senate to appoint three new members of the National Labor Relations Board. He said the move was part of a policy that affects the economy “based not upon what’s right for the American worker, but instead, what’s right for their politics.”

Gingrich, too, slapped Obama on the subject, and urged Congress to defund the agency.

The NLRB was at the center of a recent controversy in South Carolina when it filed a lawsuit accusing Boeing of building a non-union plant in the state for construction of its 737 airplane to retaliate against past Machinists union strikes at a factory in Washington state.

The lawsuit was dropped after the company and union agreed on a new contract.