Then you shall help (or at least lose the opportunity of preventing) the (D) nominee, presumably Hillary Clinton, become President. That's just a fact, and I'm just pointing it out; there's no sense in being in denial about this fact. If you're going to insist upon this "conscience vote", at least be honest with yourself about the effects, that's all I ask.
So, by not voting for someone who holds views totally opposite of what I believe, I am in fact voting for someone who holds views totally opposite of what I believe. I should just check my morals at the voting booth door and blindly follow the party.
Since you didn't get my earlier point, I will ask again. If Rudy suddenly decided to be anti war, and got the nomination, would you vote for him? Especially since not voting for Rudy would be a vote for Hillary (according your logic).