You hear Trump fans say, "He says what we think." Aka: he legitimates their thoughts.
People have always thought about physical violence, and sexual assault, and getting away with theft, and bald-faced lying with impunity. People think evil. But society establishes rules. We call them norms, or mores, as in the word "morals." They're a code of conduct that preserve civilization.
Sometimes these mores are wrong, as when they prevented gays from living authentically.
Sometimes these mores are hypocritical, as when we pretend that African Americans are treated equally or no one cheats on their marriage.
But they serve a purpose. They are the basis on which people conduct themselves and interrelate in a society.
And then comes Trump. "He says what we think," they say. And suddenly, interpersonal violence, lying in public, sexual assault are no longer just thoughts. Now they are legitimated actions, because the leader of the free world is not only saying them out loud, he is opposing society's norms of behavior and saying they no longer apply. "If you see somebody getting ready to throw a tomato, knock the crap out of them, would you? Seriously, OK? Just knock the hell ... I promise you I will pay for the legal fees. I promise, I promise," he said on Feb. 1, 2016.
"Trump gets away with anti-social activities, so maybe I can as well. Maybe they're actually not wrong. Maybe they are what a 'real man' does." And so it goes.
No, Trump didn't murder Jews in a Pittsburgh synagogue, or assault dancers in a club, or send pipe bombs to his political opponents. He just legitimates these transgressions with his words, actions and lies, and frees those who have the thoughts to perform the deeds. No one can connect the crimes to Trumps words or actions, but he is the symbolic exemplar who legitimates anti-social transgressions that are undermining the social fabric of our democracy.