On election night in Beverly Hills, Jason Blum, the hot shot horror-movie producer, was accepting an award at the Israel Film Festival. The polls in a string of midterm contests were closing, and Mr. Blum, a vocal critic of President Trump, was talking about how much was at stake.

“The past two years have been hard for all of us who cherish the freedoms we enjoy as citizens of this country,” Mr. Blum said.

That’s when the crowd of mostly Jewish producers and power brokers started to chant, “We like Trump!” An Israeli man stepped onto the stage to try to pull Mr. Blum away from the microphone as the crowd at the Saban Theater Steve Tisch Cinema Center cheered.

“As you can see from this auditorium, it’s the end of civil discourse,” Mr. Blum said, as security rushed the stage to help him. “Thanks to our president, anti-Semitism is on the rise.”