Trump said that people who didn’t applaud his State of the Union address are treasonous.
“I said, ‘We have the lowest Black unemployment in the history of our country.’” Trump stated recently in a speech. “It was like — it was a game, you know, they play games. They were told, ‘Don’t make a facial movement.’ And I’m talking about, you have the lowest Hispanic unemployment in the history of our country — this isn’t me saying — this is the charts, the polls. We have the lowest in the history of our country. Dead silence. Not a smile. You’ve got half of the room going totally crazy, wild. They loved everything. They wanna do something great for our country. And you have the other side, even on positive news, really positive news like that, they were like, death and un-American. Somebody said treasonous, I mean, yeah, I guess, why not? Can we call that treason? Why not? I mean they certainly didn’t seem to love our country very much.”
Another party not supporting a person's speech is a first amendment right, so implying that those who don’t believe in you are “treasonous” is both wrong and unconstitutional — Trump can’t simply force other people to agree with him.