The violence that broke out Thursday night in San Jose, California, during and after a Donald Trump rally has raised fears that the next five months will see increasingly heightened confrontations between Trump protesters and admirers. It’s also led to the frightening thought that violent resistance to a candidacy based on the promise of violence might in some quarters be considered a rational strategy.

To discuss what the protests mean and how to think about the ways to oppose a candidate who makes frank appeals to racism and xenophobia, I called up Todd Gitlin, an expert on politics and the media and a professor of journalism and sociology at Columbia University. He has has written extensively about the 1960s and protest movements. Our conversation has been edited and condensed.

Isaac Chotiner: What did you make of the events in San Jose Thursday night?

Todd Gitlin: My thoughts ran back to an incident in San Jose in 1970 when Nixon was speaking from a rally and got up on his car and he flashed his V-sign with a big grin. Later, he said to one of his hangers-on, “They hate it when I do that.” He was courting a venomous display of rage. I don’t think Trump was necessarily deliberately inciting this, but I think he properly regards these collisions as food for his wilder beasts, and he loves it.