No person alive should vote for Donald Trump.
Those on the right should reject him for his lack of conviction, his narcissism, his worship of mammon, his dishonesty, the fact that his bigotry will harm his party, his open commitment to violating NAFTA and other treaties that the U.S. signed in good faith making him an open opponent of our Constitution, his libertine past, his lack of any religious credentials whatsoever despite proclaiming his faith, his casual anti-Semitism (on display when he talked to a group of Jews and talked about how the people in the room clearly all knew how to negotiate well), and his total willingness to say or advocate anything that is popular. The very fact that he initiated the birther nonsense should disqualify him from anyone's vote. Voting for no one would be preferable: Such a man should not be representing us internationally or have his finger on the button.
Those on the left, of course, should reject him for being a racist, sexist, classist pig.