There are a lot of angry conservatives tonight who were denied their third choice.
A third party candidacy could result in a deadlocked election where McCain-Huckabee would have to make meaningful concessions to win. At the very least, it would give conservatives someone to show up and vote for at the top of the ticket to save conservatives down ticket.
I am 47. I first voted for Reagan in 1980. Since then, I have always voted Republican. Two Reagans, Four Bushes and a Dole. I am as reliable a Republican voter as you could ask for. But if McCain wins the nomination, I am ALL OVER a third party conservative (or if need be, libertarian) candidate.