If I believed that Clinton was going to start World War III, and that Trump would stop it, then I would vote for Trump despite all of his nastiness.

In reality, I believe Trump is much more likely to start WWIII, which is yet another reason to be opposed to him, but it is extremely uncharitable to assume that all of his supporters support everything that he does. I think most Republican voters simply believe he's the lessor of two evils. I strongly disagree with them, but respect the democratic process.