One thing did in Mitt Romney in 2008: Mitt Romney. Republicans didn't like him in 2008 and it is clear that he is no more popular in 2012. He can't rise about 20-25% in the polls because most Republicans will tell you that their favorite candidate is Anyone But Romney.
IMO, Romney would have fought against Hussein better than McAmnesty. I grant his weaknesses...but I don’t think he would’ve been the puss McInsane was.