Elon Musk is set to hit the campaign trail as a surrogate for Donald Trump in the closing weeks of the election, though polls show he is broadly unpopular.

Mr. Musk, the world’s richest man and the leader of Tesla and X, delivered a dark warning during an animated appearance at former President Donald J. Trump’s rally.

A movie Trump doesn’t like is gonna get sued. A tech mogul he doesn’t like, he wants to put in prison. It’s not free speech if only Trump’s admirers get to do it without consequence.”