MANCHESTER, N.H. — Mitt Romney brushed aside rivals' criticism Saturday night in the opening round of a weekend debate doubleheader that left his Republican presidential campaign challengers squabbling among themselves and unable to knock the front-runner off stride.

Three days before the first in-the-nation New Hampshire primary, Romney largely ignored his fellow Republicans and turned instead on President Barack Obama. "His policies have made the recession deeper and his policies have made the recovery more tepid," he said, despite a declining unemployment rate and the creation of 200,000 jobs last month.

Over the course of the lively 90-minute debate, there were attacks aplenty as Romney's five rivals vied to emerge as his principal rival in the primaries ahead. The former Massachusetts governor won an eight-vote victory in the Iowa caucuses last Tuesday and is far ahead in the pre-primary polls in New Hampshire.

That leaves his pursuers little time to stop his rise, and, all but conceding New Hampshire to the former governor of next-door Massachusetts, they're mostly focusing their efforts on the South Carolina primary on Jan. 21

Texas Rep. Ron Paul assailed Rick Santorum as a "big government person," an allegation the former Pennsylvania senator disputed. Santorum finished a close second to Romney in Iowa this week, with Paul coming in third.

Paul, who has called former House Speaker Newt Gingrich a "chicken hawk" who has not served in the military, drew withering criticism in return. "I personally resent the kinds of comments and aspersions he routinely makes," Gingrich said.

Paul got the last word, saying emphatically, "When I was drafted I was married and had two kids, and I went." He was an Air Force surgeon in the Vietnam War era.

Gingrich was fourth in Iowa, Perry fifth and Minnesota rep. Michele Bachmann, who has since quit the race, was last. Huntsman did not compete there, hoping to make a splash in New Hampshire.

Romney appeared uncertain only once, when he was asked if states have the right to ban contraception. He avoided a clear answer, suggesting the question was irrelevant.

"No. States don't want to ban contraception," he said. In a ruling in 1967, the Supreme Court said married couples have a right to use contraception, a finding that has been expanded in subsequent opinions

Romney, who often touts his business background, was attacked in the opening moments of the debate.

Santorum went first, dismissing him as a mere manager. "Being a president is not a CEO. You've got to lead and inspire," he said.

Gingrich followed a few moments later, referring to published accounts that described how some workers were laid off after Bain Capital, the firm Romney once led, invested in their companies and sought to turn them around.

He said Romney should be judged on the basis of whether "on balance, were people better off or worse off by this style of management."

Unruffled, the former Massachusetts governor retorted that Bain had created 100,000 jobs on balance, and that a businessman's experience was far better to fix the economy that a lifetime spent in Washington, D.C. "I'm very proud of the fact that the two enterprises I led were successful," he said, referring to Bain and another firm.

More than an hour later, Romney turned one question about his vision for the country into an attack on Obama that is part of his standard campaign speech. While his rivals stood by silently, he accused the president of trying to turn the United States into a "European-style welfare state."

Perry, who flirted with quitting the race after Iowa, emphasized that he was an outsider in the race as he sought to lump his rivals into one, unappealing category.

"I think you've just seen a great example of why I got in the race. ... I'm the only outsider," he said as he watched Santorum, Paul, Gingrich and Romney clash.

Former Utah Gov. Jon Huntsman dismissed much the back-and-forth as "insider gobbledygook ... a lot of political spin," saying he would focus on more important questions such as national security.

He drew one of the few barbs that Romney directed at a fellow Republican during the evening.

"I'm sorry, Governor. You were the last two years implementing the policies of this administration in China. The rest of us on this stage were doing our best to get Republicans elected across this country and stop the policies of this president from being put forward."

There were a few light moments.

At one point, Paul was interrupted by a bell meant to indicate his time to speak had expired. "There it goes again," he said.

Santorum replied instantly: "They caught you not telling the truth, Ron."

The intramural skirmishes reflected the state of the race — Romney the acknowledged front-runner under attack from his rivals, who face an increasingly urgent need to emerge as his main conservative challenger.

The debate at Saint Anselm College was the first in more than three weeks, and the first since Bachmann dropped out of the race. The candidates faced a quick turnaround for the second debate, set for Sunday morning in Concord.