I know folks who for the lack of a true conservative candidate on the ballot voted for Zero for that very reason.
Sit home, for crying out loud...why put that on your resume for Judgement Day?
Last year I felt like I would be in the camp that would vote 3rd party, then reality struck. I voted for Mitt.
I suppose some folks felt like they needed to punish the GOP-e for giving them a liberal from Massachusets.
I full expect complete implosion of the Republican Party at this point. Demographic changes that Pat Buchanan warned us about I believe are kicking in now rather than 20 or 30 years in the future.