Trump Insults "War Hero"
While Trump stated something truthful, he crossed the line that his supporters find sacred. He "insulted" John McCain, POW.
Trumps is determined to build a wall to keep brown people in their places. That wall, combined with his bigotry, is what appears to keep his supporters loyal.
Is there a line Trump can cross to weaken his support? It doesn't seem so. Bigotry and superstition are powerful means to control minds.