Trump fails at being a credible candidate because he has no track record of being conservative. To the contrary.
Just because he started mouthing platitudes 2 months ago about fighting immigration and can handle the media is no reason to believe he will govern according to anything like a conservative viewpoint.
He published his book, time to get tough, in’11. I keep asking the anti-Trumps to quote me one liberal position/idea cited therein; so far, crickets.