"My polls show me to be a worse candidate than Rick Perry or anyone else you can name," Akin never said, but it sounds like a great quote.
The following description of Akin's candidacy comes from the Fix column:
It’s a very rare candidate — Christine O’Donnell, we are looking at you — who can take a race that his/her party will win and turn it abruptly into a race that the party will lose. Missouri Rep. Todd Akin is just such a candidate. Had Akin never agreed to a single media interview or debated Missouri Sen. Claire McCaskill (D) after he won an August Republican primary, we would almost certainly be talking about him as the next senator from the Show Me State. But Akin chose a different route – telling a local news channel that “legitimate rape” rarely causes pregnancy. Um, what? From that day onward, Akin had no chance to win. Everyone knew that, except for Akin and his increasingly small political inner circle who insisted he was staying in the race as a matter of principle. (What principle? The one about costing your party a Senate seat?) Akin wound up losing by 16 points in a state that Mitt Romney won by 11 points. Underperforming your presidential nominee by 27 points earns you a spot on the Fix’s worst candidate list every time.