As someone with strong libertarian instincts, this is a dilemma I've struggled with for most of my voting life:
On Monday, former Congressman and staunch libertarian Ron Paul (R-TX) campaigned for Virginia Republican Governor candidate Ken Cuccinelli and said Virginias would be giving up on liberty if they voted for Democrat Terry McAuliffe in Tuesday's election and would be "insane" if they voted for so-called libertarian Robert Sarvis, the third-party candidate who may siphon enough votes from Cuccinelli to spoil the election.
You know the Libertarians are never going to win, but the more votes they get, the more credibility the party (or, rather, its philosophy) has and the more likely it is that the GOP will adopt some of its ideas. But in a tight race, voting for the Libertarian risks defeating someone who is sort of for limited government and giving the victory to someone who absolutely isn't. It's throwing out second-best in favor of the worst.
I guess this is the same sort of dilemma statist progressives faced early last century when they had to decide to vote for the Democrat or the Socialist. They have no problem today; Democrats have adopted so much of the Socialist agenda there's no real point in a Socialist running. Would that the GOP could achieve the same degree of libertarianism as the Demorats have of socialism!