Trump Is A Boggart

In the world of Harry Potter, a boggart is the manifestations of your worst fears. Whatever you fear most, a boggart assumes that shape.

Trump is a real life boggart, except he doesn't exactly take the shape of his audience's fears, but rather gives voice to them.  The white hot fear that the Trumpenproletariat has of brown people and brown Muslims and Mexican Muslims and "teh blacks" and "those people" are perfectly distilled by Trump and projected back for the audience to experience.

While we're at it, Ted Cruz is Lucius Malfoy, Marco Rubio is Gilderoy Lockhart, Hillary Clinton is Hermione Granger, Bernie Sanders is Mad-Eye Moody and Jeb Bush is someone who died before the book even began.