HANOVER, N.H. - The leading Republican presidential contenders say President Barack Obama has failed to lead, accusing him of indulging in too much regulation and too much politicking.

In a televised debate Tuesday night, former Massachusetts Gov. Mitt Romney and Texas Gov. Rick Perry went after the president instead of each other at the start, laying the blame for the nation's weak economy at Obama's feet.

Romney said Obama "has divided the nation and tried to blame other people" for the stubbornly high unemployment rate.

Perry said the government must open the way for more production of domestic energy. The nation must "pull back those regulations that are strangling American entrepreneurship," he said.

Another candidate, businessman Herman Cain, repeated his call for replacing the U.S. tax code with a 9 per cent national sales tax and a 9 per cent levy on personal and corporate income.

Given the chance to assail Wall Street for economic problems, Minnesota Rep. Michele Bachmann instead blamed too much federal regulation.

Former House Speaker Newt Gingrich blamed Federal Reserve Chairman Ben Bernanke for the recession.

Also debating were Rep. Ron Paul of Texas, former Utah Gov. Jon Huntsman and former Sen. Rick Santorum of Pennsylvania.

Meanwhile, Obama defended his economic policies and criticized his Republican foes in a visit to the general election battleground of Pennsylvania.

Hours before the candidates met in Hanover, Romney picked up New Jersey Gov. Chris Christie's endorsement, which he hopes will help cement his support among the party establishment and nurture an image that he's the party's inevitable nominee.