It was a clash of economic plans tonight as Republican candidates presented differing approaches to the jobs, the economy, government spending and taxes during tonight’s Washington Post/Bloomberg debate in New Hampshire.

As the eight GOP candidates jockeyed, the debate appeared to do little to shake former Massachusetts Gov. Mitt Romney’s position as the front-runner. Much of the debate focused on the former Massachusetts governor, but businessman Herman Cain also got to repeatedly showcase his “9-9-9” plan for tax reform. Cain, seeking to capitalize on his recent uptick in the polls, touted what he he called “a pretty bold plan.”

Romney sought to look more presidential than his fellow candidates, taking swipes at Cain’s proposal and an energy-jobs plan offered by Texas Gov. Rick Perry. Romney dismissed their schemes as being too simple to address the broad and complex challenges he would face as president.

Simple solutions are good, he said. “But they’re often inadequate...We can’t focus on just taxes or just energy.”

Romney also promised action on “day one” of his presidency, including standing up to China on trade policy and issuing states waivers on “Obamacare.”

Other candidates, too, took shots at Cain’s plan, with Minnesota Rep. Michele Bachmann mining it for a laugh line. “Take the 9-9-9 plan and turn it upside down,” Bachmann said, alluding to the number 6-6-6, a demonic signifier. “The devil is in the details.”

Romney didn’t just aim at his rival candidates, he came out swinging at President Obama. He noted that Obama had promised “hope and change.”

“Instead, he’s divided the country and blamed others,” he said.

Meanwhile, the focus on Cain and his tax plan appeared to come at Perry’s expense. The governor is seeking to overcome his reputation as a weak debater with a strong performance tonight. Perry grabbed relatively little airtime and appeared defensive when asked to outline his plan for economic recovery, saying he will detail his plan, whose centerpiece is a proposal to create new energy jobs, over the next week. But pressed to reveal it onstage, the governor demurred.

Questions that have flared in the recent days and hours of the campaign about race, religion, and personal character were nowhere to be found as the candidates sought to distinguish their economic plans.

And it was former House Speaker Newt Gingrich (Ga.) who got the first applause line of the night from the crowd, when he took aim at a range of Democratic targets, including some of the “Occupy Wall Street” protestors, Rep. Barney Frank (D-Mass.), former Sen. Chris Dodd (D-Conn.) and Federal Reserve Chairman Ben Bernanke.

Former Utah governor Jon Huntsman, Rep. Ron Paul of Texas, and former Pennsylvania Sen. Rick Santorum also attempted to stand out on the crowded stage.

Earlier on Tuesday, Romney bolstered his status as the top candidate with a significant endorsement. Hours before the candidates met in Hanover, Romney captured the blessing of New Jersey Gov. Chris Christie’s, which he hopes will help solidify his support in the GOP establishment and nurture an image that he’s the party’s inevitable nominee to run against Obama in the general election.

Romney, a former governor of neighboring Massachusetts, stood alongside as Christie declared, “I’m here in New Hampshire for one simple reason: America cannot survive another four years of Barack Obama, and Mitt Romney’s the man to lead America and we need him now.”

The economy, the issue most expected to motivate voters during the 2012 elections, was supposed to be the main topic of tonight’s GOP debate. But there is a chance the subject could change, if the hours leading up to the debate were any indication. .

Minutes after accepting Christie’s endorsement, Romney called on Perry “to repudiate the sentiment and the remarks” from an ally who likened Romney’s Mormonism to a “cult.”