Violent activists at the University of California have prompted Sen. Bernard Sanders to side with an unlikely ally: Ann Coulter.

Anti-Trump protests, threats of violence aimed at conservative speakers, and the cancellation of a scheduled April 27 speech by author Ann Coulter has Vermont’s senator worried about free speech on Berkeley’s campus.

“I don’t like this. I don’t like it,” Mr. Sanders told The Huffington Post at an Omaha, Nebraska, event last week, the website reported Saturday. “Obviously Ann Coulter’s outrageous ― to my mind, off the wall. But you know, people have a right to give their two cents worth, give a speech, without fear of violence and intimidation.”

Mr. Sander’s comment comes in stark contrast to former Vermont Gov. Howard Dean, who has said that Ms. Coulter’s social commentary is not protected by the First Amendment.

“Hate speech is not protected by the first amendment,” Mr. Dean tweeted April 20.

The comment served as the catalyst for a next-day op-ed in The Washington Post: “No, Gov. Dean, there is no ‘hate speech’ exception to the First Amendment.”

“There is no hate speech exception to the First Amendment,” wrote UCLA professor Eugene Volokh, who teaches free speech law. “Hateful ideas (whatever exactly that might mean) are just as protected under the First Amendment as other ideas. One is as free to condemn, for instance, Islam — or Muslims, or Jews, or blacks, or whites, or illegal immigrants, or native-born citizens — as one is to condemn capitalism or socialism or Democrats or Republicans.”

Protests at Berkeley broke out April 15 between anti-Trump and pro-Trump groups and resulted in 20 arrests. A Feb. 1 speech by pundit Milo Yiannopoulos was also derailed when masked individuals broke down barricades and destroyed property.

“We shut down the event. It was great. Mission accomplished,” a protester told CNN at the time.

Mr. Sanders told Huffington Post that such attempts to stifle free speech are a sign of “intellectual weakness.”

“Confront her intellectually. Booing people down, or intimidating people, or shutting down events, I don’t think that that works in any way,” the Democrat told the website.