US election 2012: GOP hunt for mystery 'third man' who could beat Obama Some have called for a "white knight" candidate to ride into as many late primary elections as still possible, before trying to seize delegates from other states at the convention in Tampa. Names frequently proposed include Jeb Bush, the former Florida governor and brother of President George W., Chris Christie, the New Jersey governor, and Sarah Palin, the 2008 Vice-Presidential nominee. All have previously ruled themselves out of this year's contest. Calls for an alternative choice will grow louder if Mr Romney, a relative moderate former Massachusetts governor, fails to win a crucial primary in his home state of Michigan next week. However, having trailed Mr Santorum by nine percentage points there last week, Mr Romney has closed the gap to a virtual tie, according to RealClearPolitics polling aggregates. He leads Mr Santorum by eight points in Arizona. Both states hold their primaries on Tuesday. Meanwhile Jon Huntsman, the former Utah governor who dropped out of this year's race after a poor showing in the first two primaries, called for an independent candidate to shake up the entire election. "I think we're going to have problems politically until we get some sort of third party movement or some alternative voice out there that can put forward new ideas," Mr Huntsman told MSNBC. It has been suggested that Mr Huntsman - who endorsed Mr Romney but is no friend of his fellow Mormon - may himself lead a campaign for Americans Elect, a third-party movement. However he added: "That ain't gonna be me, by the way ... I'm not interested in that. The mounting speculation followed a debate in Mesa, Arizona, in which Mr Santorum, a Right-wing former Pennsylvania senator, gave a faltering performance and failed to capitalise on a recent polling surge. He instead allowed Mr Romney - who won the debate only by default - to paint him as a tainted Washington insider, admitting that he had voted for things he disagreed with as a US senator because sometimes "you take one for the team." Amid unprecedented public loathing for Congress, his remarks threatened to confirm Mr Romney's central attack that Mr Santorum is too compromised to deliver the radical overhaul of the capital that Republican activists are demanding. "I wonder which team he was taking it for," Mr Romney told supporters at a rally in Arizona last night. My team is the American people, not the insiders of Washington. He added: "I don't know if I've ever seen a politician explain in so many ways why it was he voted against his principles."