US election 2012: Mitt Romney's potential Vice-President picks The young Cuban-American senator would bring spark and glamour to campaign that has often lacked both. He could also help Romney overcome his major poll deficits with Latinos and may help deliver the crucial swing state of Florida for the Republicans. But he has been in the Senate less than two years and vulnerable to accusations he is not qualified to be President. He was also briefly a Mormon before reverting to Catholicism, which may raise concerns among Evangelicals. Portman also brings a wealth of Washington experience, having served in the Senate, House and twice in George W Bush's cabinet. However, he is virtually unknown to the American people and has the demeanour of a bureaucrat rather than a national politician. Chris Christie, Governor of New Jersey: the bulldog The larger-than-life governor would relish the chance to bring the fight to Obama on a national stage. Unrelentingly blunt and a gleeful political street brawler, Christie is known for his thundering speeches and for taking on and defeating hecklers. He backed Romney early and stayed loyal throughout the primary. Romney aides worry that his star power might overshadow their stiff and measured candidate. The party may also balk at having two relative moderates from the North East on the ticket. Paul Ryan, Wisconsin Congressman: the fiscal puritan The young congressman is the author of the Ryan Plan, a conservative fantasy budget that would slash government spending and privatise Medicare, the US's national insurance plan for pensioners. His extreme fiscal philosophy has made him a darling of the Tea Party and earned generous praise from Romney himself. Ryan is a telegenic young figure but his views make him a lightning rod for Democrat attacks. Obama has already begun campaigning against his plan, calling it "thinly-veiled social Darwinism."