"He didn't create the recession, but he made it worse and longer," the former Massachusetts governor said in the second debate of the 2012 election season but the first in which he shared the stage with his fellow Republicans.
"This president has failed. And he's failed at a time when the American people counted on him to create jobs and get the economy going," said Romney, who leads in national polls and in New Hampshire and Iowa.
Former U.S. House Speaker Newt Gingrich, whose campaign collapsed last week when virtually his entire senior strategy team resigned, described the Obama administration as an "anti-job, anti-business, anti-American-energy destructive force" and labeled the ongoing economic downturn "the Obama depression."
Romney also called for U.S. troops to return from Afghanistan "as soon as possible," but consistent with field commanders' recommendations.
"Our troops shouldn't go off and try to fight a war of independence for another nation," he said.
U.S. Rep. Ron Paul of Texas said he "wouldn't wait for my generals."
"I'm the commander in chief. I tell the generals what to do," he said.
Rep. Michele Bachmann of Minnesota, who announced her presidential candidacy as the debate at St. Anselm College in Goffstown, N.H., began, called for rolling back the U.S. Environmental Protection Agency, which she said should be renamed "the job killing organization of America."
She also said, "As president of the United States, I will not rest until I repeal Obamacare," using a pejorative nickname for the Patient Protection and Affordable Care Act, which Obama championed and signed into law last year as part of healthcare reform.
Gingrich called for de-funding the National Labor Relations Board, responsible for conducting labor-union elections and investigating and remedying unfair labor practices.
Romney suggested the functions of the Federal Emergency Management Agency, responsible for coordinating U.S. disaster responses that state and local authorities can't handle, should be given to state governments, or if possible, the private sector, The Wall Street Journal reported.
Former Godfather's Pizza Chief Executive Officer Herman Cain called for the privatization of Social Security.
The candidates also called for the repeal of Obama's 2010 Wall Street reform law, considered the largest financial-system overhaul since the 1930s, as well as the 2002 Sarbanes-Oxley law on accounting approved in the wake of the mammoth Enron and WorldCom scandals, the Journal said.
Absent from the debate were potential candidates former Utah Gov. Jon Huntsman, until several weeks ago Obama's ambassador to China, and former Alaska Gov. Sarah Palin, the 2008 Republican vice presidential nominee.