That can only work if the Republican party puts up a RINO like McCain or Romney.
Most conservatives would take a decent conservative over Obama but if the RNC put forth an Obama(R), yes a 3rd party could be a spoiler.
Really? Last time around, they DID put up McCain and there was no significant 3rd party challenge from the right. Further, down the stretch in the primaries, when McCain was leading, who was the officially sanctioned anti-McCain vote, the candidate Limbaugh and others were settling on? Romney. Wasn't Ann Coulter for Romney as well?
So why would the same two guys spawn any different response from GOP voters at large?