Republican presidential hopefuls former US Senator Rick Santorum (R-PA), US Rep. Michelle Bachmann (R-MN), former Speaker of the US House of Representatives Newt Gingrich (R-GA), former Massachusetts Governor Mitt Romney, US Rep. Ron Paul (R-TX), former Minnesota Governor Tim Pawlenty and former Godfather's Pizza CEO Herman Cain (L-R) participate in the first New Hampshire debate of the 2012 campaign at St Anselms College in Manchester, New Hampshire June 13, 2011. [Photo/Agencies]

'A DEFEATIST ATTITUDE'

The candidates declined to join in Democratic criticism of Pawlenty's economic plan for relying on a rarely achieved 5 percent growth to fund his tax cuts. Pawlenty accused his critics of a failure of ambition.

"This idea that we can't have 5 percent growth in America is hogwash. It's a defeatist attitude," he said.

Romney, who failed in a 2008 bid for the Republican nomination, leads the Republican pack in most polls but is an uneasy front-runner in a group that has drawn complaints from some in the party for being a weak field.

US Representative Michele Bachmann, who had not entered the race before Monday, said she had just filed the paperwork to formally run for president. Jon Huntsman, the former governor of Utah who served as US ambassador to China under Obama, also is expected to enter the race in the next few weeks.

The Republicans showed few policy differences during the debate. They mostly backed Representative Paul Ryan's budget  proposal that would scale back the Medicare health insurance plan for the elderly and disabled, and did not support raising the debt ceiling without dramatic spending cuts.

"We're not that far apart on all the big issues," said former pizza executive Herman Cain.

The debate on the campus of Saint Anselm College in Manchester, New Hampshire, was an early look at the contenders for the activists in the early-voting state who will play a critical role in the 2012 nominating battle.

The presidential election will be held in November 2012.

Romney, Bachmann and Newt Gingrich skipped a lightly attended debate last month, but appeared on Monday with four contenders who participated in the first one - former Senator Rick Santorum, Pawlenty, Cain and US Representative Ron Paul.

Bachmann, a fiery conservative from Minnesota, has earned a following on cable TV news shows and among Tea Party activists with her outspoken condemnations of Obama and Washington insiders. She promised that Republicans would oust Obama in 2012.

"President Obama is a one-term president," she said.

Gingrich, a former speaker of the House of Representatives, was not asked about last week's desertion by most of his senior campaign staff over disagreements on the future of his campaign.