Referring to Musk’s recent pronouncement that he’d never voted Republican until this June, Trump said that contradicted with what Musk had told him. Trump followed with an expletive description of the world’s richest man and voiced his judgment on the Twitter Inc. acquisition deal that Musk struck but has since decided to withdraw from, calling it “rotten.”

Trump’s comments come in the wake of Musk expressing a leaning toward Ron DeSantis, currently the Florida governor and a favored Republican candidate for the 2024 presidential election. DeSantis is, so far, the strongest potential competitor to Trump for the Republican nomination, and Musk’s influence—now numbering over 100 million followers on Twitter alone—could make his endorsement significant.

“I’m undecided at this point on that election,” Musk said in a June 21 interview with Bloomberg News. He said he will commit $20 million to $25 million to support his chosen contender.

After stressing the importance of free speech online, Trump urged the crowd to join his own Truth Social, a network closely modeled on Twitter’s interface and functionality where the retweet button has been replaced with a “retruth” option.