The issue with Trump is that he's being a classic political opportunist in the same way George Wallace in Alabama lost elections when he didn't stand for segregation, switched, and became a populist candidate that had a lock on the governorship for decades.
Trump is a smart man. He's also heavy into the casino, hotel, and restaurant business. You know who staffs those businesses -- especially in a way they can turn a labor-costs-based profit? Immigrants. Trump knows this.
But when it comes to populist politics, the formula around the world is to appease a growingly (and rightfully) anxious working class, point to immigrants and apply threats about crime and jobs (since they can't vote anyway), and bring to a boil.
It's what's going on now in the Dominican Republic, Myanmar, Hungary (and much of Europe for that matter), etc. It's a tired but true formula.
THAT is what Trump knows.