If you are absolutely sure how your state is going to vote, and it's not to your liking, then it may make sense to vote for the Losertarian or the Constipationalist, or whomever. Your guy might actually break a percent! At least, there would be a number in the returns to shake a stick at.
E.g., the 2000 US Senate race in Massachusetts, in which Libertarian Carla Howell got 11.3% (!), and Republican Jack E. Robinson got 12.23%, Fat Teddy winning, of course, with 69.11%.
But if there's any doubt whatsoever as to the final outcome, then you need to vote for the R, even if he sucks!
How interesting that on a board dedicated to Conservatism and the Constitution, we find a cadre of GOP-e party hacks who use derogatories to refer to Conservatives and Constitutionalists in demeaning fashion, which I think, reveals who and what they truly are.
Plants, wolves and agitators.