If Donald Trump is really anything other than the hawkiest of the hawks, then why is he being supported by Rudy Giuliani?
The people who are voting for Trump think that he is going to nuke Mexico. That is why they are voting for him.
John Kasich would make a better President than Hillary Clinton, as might whoever the GOP had drafted on the second round of voting at the Convention. Of course, that person might be Kasich.
Short of a Sanders nomination, an at least relatively acceptable Republican nominee is the last hope.