It lacked the showbiz-style pizazz of a Donald Trump entrance, but a Republican forum here Friday night featured something else — top-tier political figures sharing the billing, signaling to grass-roots activists that this was the kickoff of the GOP’s 2012 race for the White House.

While Trump was a no-show, the attendees did include former Massachusetts governor Mitt Romney, Rep. Michele Bachmann (Minn.), businessman Herman Cain, former Minnesota governor Tim Pawlenty and former Pennsylvania senator Rick Santorum. It marked the first time that Romney has appeared with other prospective rivals for the 2012 nomination.

The Republicans joined in hammering President Obama over high gasoline prices, the role of government, soaring debt deficits and health care.

Billed as a jobs summit and sponsored by the group Americans for Prosperity, the 90-minute session also brought prominent conservative lawmakers Sen. Jim DeMint (S.C.) and Rep. Steve King (Iowa) to this crucial early-voting primary state, where fiscally oriented tea-party Republicans form a vocal and active part of the base.

The forum gave potential candidates a chance to test-drive the sort of fiscal messages and attacks on Obama’s policies that core conservatives are eager to hear.

Pawlenty — who let slip Friday that he was running for president, then quickly said he was still only thinking about a run — opened his remarks with a series of questions that will likely form the basis of much of the GOP message for 2012.

“You had enough of $4-a-gallon gas? You had enough of unbearable levels of unemployment? You had enough of a federal government that is out of control?” Pawlenty roared, as the crowd shouted “Yes!”

“You had enough of Barack Obama? Yeah, me, too.”

Romney, who owns a home in the Granite State and leads in most polls of New Hampshire Republicans, mixed biography with an emphasis on faith and family. He also nodded at least obliquely to social issues and criticized Obama for high unemployment and gas prices.

There was a sharp difference in the way Pawlenty and Romney dealt with past positions that are anathema to conservative Republicans — Pawlenty’s one-time support for cap-and-trade legislation, and Romney’s enactment of a health-care system in Massachusetts that Obama would largely emulate.

Pawlenty offered an abject apology.

“I changed my position and said it was a mistake,” he said. “It was stupid, and I’m sorry.”

Romney said the Massachusetts bill dealt with such problems as pre-existing conditions and the cost to taxpayers of funding emergency-room care for people without insurance.

“It is not perfect,” he said. “Some parts of it worked, some didn’t.”

He went on to say he would fight to repeal the federal health-care law and would give waivers to all 50 states to opt out of the new system.

New Hampshire activists in the audience said afterward that, while they were impressed with both Pawlenty and Romney, they were particularly struck by several of the other candidates.

“I’m most confident in Bachmann and Cain, and Santorum’s heart is in the right place,” said Donald Ewing, 68, a retired computer programmer.

Cain’s strong pro-business message resonated with the audience, as did Bachmann’s prescription for dramatically cutting the size of the federal government.

High gas prices have given the Republicans a new line of attack against Obama, and the prospective presidential candidates eagerly joined in Friday night.

But their critiques went much broader, extending to his economic record and his health care plan.

Romney said Obama’s inexperience had made a bad recession worse.

“He made it worse and he made it deeper and longer. . . . It’s simply inexcusable,” he said.

Bachmann said congressional Republicans should block all funding for Obama’s health-care law.

“We shouldn’t give one dime to put this Frankenstein in place,” she said.

Earlier Friday, Romney showed up at a gas station and linked gasoline prices — $3.93 for a gallon of regular — to what he said was Obama’s failure to outline an energy policy. In jeans and an open-collar shirt, Romney pumped gas into an aide’s silver Ford Escape — a stark contrast to Trump, another potential 2012 candidate, who arrived in New Hampshire on Wednesday in a helicopter and tooled around the state in a black stretch limousine.

“People are hurting, gasoline is expensive and policies of this administration that have focused solely on green technologies are not keeping the cost of gasoline down,” Romney said at the gas station. ”The president’s policies have made people very uncertain about the future of the supply of gasoline in this country, because we are not developing our own resources of oil, gas and coal in the way we should.”

Friday’s audience included a mix of establishment Republicans and tea-party and other conservative grass-roots activists. Many of them are still waiting to see who will run, after a week when Mississippi Gov. Haley Barbour bowed out, Rep. Ron Paul (Tex.) formed a presidential committee and Trump continued to flirt with a run.

Next week, South Carolina hosts the first candidate debate of the election cycle — with what could be a very few candidates actually onstage. But by early June, activists here and elsewhere expect to know much more about their options.