Has not Trump expressed support for a form of amnesty? That’s what I’ve heard from him when he talks about letting the “good ones” of those who have entered illegally live here.
He has said that he wants all the illegals to be deported and that some "good ones" would be allowed back in if they go thru the legal process. Have you read Trump's position paper on immigration? It is the best one ever presented by a Presidential candidate.
Cruz and Rubio support legalization of the lawbreakers allowing them to stay and work here, i.e., amnesty. They don't have to leave and apply outside the country to reenter.