Romney is the one that is not credible, with almost 18 years in the candidate game, Mitt Romney has one election win to show for it.
Romney took that one election win and did so poorly that he could not run for reelection, although he wanted to, and he left office with 34% approval and turned the seat over to the Democrats.
Romney invested about 150 million dollars in his poor showing in 2008 against unfunded, opponents with tiny organizations.
DINGDINGDINGDINGDING!!! And we have a winnah -- !!!
He would have won the nomination in ‘08 had not Crist endorsed McLame at the last minute in Florida. And besides, he is more credible than any other candidate you have mentioned (i.e. no one). Everyone constant bashes Romney and puts up no one else as a realistic alternative.