I believe Rick Perry was the most dangerous candidate against the Democrats in terms of the Electoral College because he would have gotten a higher Latino and rural vote than Romney. This could have flipped Ohio, Florida and maybe Virginia and either Pennsylvania or Colorado with increased turnout. However his campaign got stuck on stupid issues and never got out of the starting gate.
I think his campaign got stuck on Rick Perry being stupid. He's an absolute joke. Forget Perry's resume, he fails the basic test of competence. Obama would have smoked him.
Perry's candidacy was just about EVERYTHING WRONG with the GOP platform and party in 2012. He's a good summary of what's wrong.