Trump is off base on due process. I believe he knows better, but he's not the first Presidential candidate who panders to the "Silent Majority". I remember back in the 1970s when a survey asked folks whether or not they agreed with a number of proposals that were, in fact, the Bill of Rights. Most folks actually opposed them. Nixon played this to the hilt.
Of course, when folks get together and express the idea that maybe it isn't a good idea to increase the number of folks emigrating to America, or deporting those who are here illegally, regardless of circumstances, folks like Hillary aren't big 1st Amendment fans, so . . .