I already voted for Benedict Arnold, but in contemporary America it has to be JOHN EDWARDS.
Some may forget that he was PICKED TO BE VICE PRESIDENT on the Democratic ticket in 2004 that lost because of Ohio, and that he had a legit shot to get the nomination that Barack Obama got when the "anybody but Hillary" bandwagon was in full locomotion.
In other words, with just a little luck He'd be the freakin' president RIGHT NOW, either succeeding John Kerry in 2012 or in the slot that Obama filled.
Fast forward to cheating on your dying wife, getting caught in the most absurd lies and puerile activities, having a sex tape revealed, and facing a federal corruption trial. No doubt for a while he was the most reviled man in the country, around the time his wife expired.