Even though I don't want him to win (I also don't want any of the available candidates), I was considering voting for him in the primary because I know my state will go heavily for Trump. My vote won't make a difference.

I've done that for a while. I really want 3rd party candidates to get at least double digit vote percentages and the closer to the two parties, the better. If we can get a 3rd party candidate close enough to the 2 parties, then maybe people will actually vote 3rd party and not use the excuse that they don't want to waste their vote.