Manchester, N.H. - Republican White House hopefuls assailed President Barack Obama's handling of the economy from the opening moments of their first major debate of the campaign season Monday night and pledged emphatically to repeal the administration's year-old health care law.

"When 14 million Americans are out of work we need a new president to end the Obama Depression," declared former House Speaker Newt Gingrich, the first among seven contenders on stage to criticize the president's economic policies.

Rep. Michele Bachmann of Minnesota, invited as an unannounced contender for the 2012 nomination, used the occasion to announce she had filed papers earlier in the day to run - a disclosure in keeping with a feisty style she has employed since her election to Congress.

Obama was hundreds of miles away, vowing to continue his efforts to create jobs as the Republicans met on a stage at St. Anselm College in New Hampshire.

Former Sen. Rick Santorum accused Obama of pursuing "oppressive policies" that have shackled the economy.

Former Minnesota Gov. Tim Pawlenty labeled Obama a "declinist" who views America "as one of equals around the world," rather than a special nation.

"If Brazil can have 5 percent growth, if China can have 5 percent growth, then America can have 5 percent growth," he added, shrugging off criticism that his own economic projections were impossibly rosy.

Businessman Herman Cain, a political novice, called for eliminating the capital gains tax as a way to stimulate job creation.

Former Massachusetts Gov. Mitt Romney stressed his experience as a businessman over 25 years as evidence that he can lead the nation out of a lingering recession.

Said Rep. Ron Paul of Texas, the seventh contender on the stage: "As long as we are running a program that deliberately weakens our currency, our jobs will go overseas. And that's what's happening."

Pawlenty, sharing a stage with Romney, at first sidestepped a chance to repeat his recent criticism of the Massachusetts state health care law that Romney signed as governor. It includes a requirement for residents to purchase coverage, a forerunner of the "individual mandate" that conservatives loathe in the new federal law.

"My using "Obamneycare' was a reflection of the president's comments," Pawlenty said, referring to a word he coined in a Sunday interview.

Romney, who first sought the nomination in 2008, was the nominal front-runner. But the public opinion polls that made him so are notoriously unreliable at this point in the campaign, when relatively few voters have begun to familiarize themselves with their choices.

Nor can the polls predict the television commercials as yet un-run, or the other events that make a nominating campaign so unpredictable.

Already, this race has had its share of surprises.

Several likely candidates decided not to run - Mississippi Gov. Haley Barbour and Indiana Gov. Mitch Daniels among them - and at least one who ruled out a race is reconsidering. Texas Gov. Rick Perry has said he will decide after the state Legislature completes its current session, and former Alaska Gov. Sarah Palin's plans are still unknown.

Gingrich, quick off the mark in attacking Obama, suffered the mass exodus of the entire top echelon of his campaign last week, an unprecedented event that left his chances of winning the nomination in tatters.

And Bachmann - newest to the race - drew one of the loudest rounds of applause Monday night from a partisan debate audience when she predicted that Obama would not win re-election. He is "a one-term president," she declared.

Obama's rivals found little if anything to like in what he has done since taking office in the midst of the worst economic recession since the Great Depression.

Instead, the most conservative presidential field in memory all but said what Ronald Reagan once preached - that government was the problem.

Romney said the auto bailout was a mistake, and said more generally, "Instead of thinking in the federal budget what should we cut, we should ask ourselves the opposite question, "What should we keep?"'

Santorum criticized the financial bailout that Presidents George W. Bush and Obama backed, and Bachmann said she had worked in closed-door meetings in Congress to defeat the legislation when it was originally passed.

Pawlenty said politicians had caused the housing price bubble that contributed to the recession, and Paul blamed the recession on the Federal Reserve.

"As long as we do what we're doing in Washington it's going to last another 10 years," Paul said. "What we're doing now is absolutely wrong," he said of federal programs meant to support the housing industry.

In general, the Republicans on stage steered away of criticizing one another, and even the evident differences among them were expressed in muted terms.

Santorum said he wholeheartedly supported Wisconsin Rep. Paul Ryan's proposal to turn Medicare into a program in which the government subsidizes beneficiaries who would seek coverage from private insurance companies. Under the current system, the government pays doctors and other health care providers directly.

Pawlenty said he would have a plan of his own that shared some features with Ryan's but would differ on other points.

The program's finances are perilous, and Republican calls for fundamental change are at the heart of a roiling debate in Congress that is expected to extend into the 2012 campaign for the White House and both houses of Congress.

Cain bluntly told one questioner he was unlikely ever to receive in benefits from the money he has paid in through payroll taxes during his working life.

Gingrich, who was attacked by fellow conservatives when he criticized Ryan's proposal for being mandatory, said, "When you're dealing with something as big as Medicare ... you better slow down. ... If you can't convince the American people it's a good idea, maybe it's not a good idea."

Gingrich, Bachmann, Romney and Pawlenty all pledged to seek repeal of the health care law that Obama won from Congress earlier in his term. The others on stage hold the same position.