Rich Lowry‘s latest column at National Review Online explores the impact of high-profile protests targeting Republican presidential front-runner Donald Trump.

Donald Trump is lucky in his enemies.

Every time leftist protesters disrupt one of his events or stage a riot outside, he benefits. They aren’t on the Trump payroll, but they might as well be. The protests are catnip to cable TV — as if Trump needed any more free media attention — and provide the perfect framing for Trump’s message that only he has the strength to defy the forces of chaos and political correctness.

At California campaign stops last week, anti-Trump protesters blocked a freeway entrance, stomped on and tried to overturn a police car, threw rocks at passing vehicles, and bloodied a Trump supporter. They tried to shut down the California GOP convention where Trump spoke (he had to enter the hotel through a back entrance). And some of them were waving Mexican flags. In other words, they could have been cast in a Trump reality show about his own campaign.

These kind of protests are quickly becoming accepted as part of the scenery, but they are a noxious breach of our political norms. There is never an excuse for violence, and attempting to shut down an event because you disagree with things that are being said there is speech suppression worthy of Brown University or Oberlin College.