WEST DES MOINES, Iowa - New Jersey Gov. Chris Christie was less than five minutes into his stump speech when chants of "Make Wall Street pay" and "Put people first" rose up through the crowd.

Christie - in town to campaign in support of former Massachusetts Gov. Mitt Romney's presidential bid - seemed surprised but unperturbed.

"We're used to dealing with jokers like this in New Jersey all the time," Christie told the crowd of more than 200 that turned out Wednesday to hear Christie speak at the corporate headquarters of the Kum & Go retail and service station chain.

The crowd applauded Christie's comment and booed the two dozen or so Occupy Iowa who had caused the ruckus and were being escorted out the door by Romney staffers.

Then, as the room cleared out, Christie used the interruption to his advantage.

"They represent an anger in our country that Barack Obama has caused," Christie said to applause. "Because he's a cynical, Chicago ward politician who runs for office and promises everything and then comes to office and disappoints."

Christie, a popular Republican who felt compelled to go on television earlier this year to announce that he would not run for president in 2012 despite the efforts of some party leaders like Iowa Gov. Terry Branstad, said Romney is the "most qualified to be president."

His stumping for Romney comes as the former Massachusetts governor has fallen behind U.S. Rep. Ron Paul of Texas and former House Speaker Newt Gingrich in recent polls and in advance of two Iowa debates that will feature the seven major Republican candidates seeking the nomination.

Christie's message seemed to be that Romney might not be the only answer, but he was the best one.

"If you're looking for the candidate who agrees with you on everything, buy a mirror," he said. "What we need to be concerned about is not about being Republicans first, but being Americans first. It's up to us to save our country, and it starts in Iowa."

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Still, there seemed to be a feeling among some in the crowd that favored a Christie run.

During a short question-and-answer session in which he fielded queries on veterans' health care and foreign policy, he also was asked whether he would be on the vice presidential ticket and or whether he might run for the White House in the future.

Christie dismissed the former saying he wouldn't say "no" outright because he hasn't been asked but indicated the idea didn't appeal to him.

On the latter, he said his term as governor is up in 2013 and if he seeks and wins another term he'd "be looking for a job in 2017."

But he took some pains to bring the conversation back around to Romney's current effort and the Jan. 3 caucuses.

"I guarantee you this," he said. "If Mr. Romney wins Iowa on January 3, he is going to be the next president of the United States."