DALLAS

President Donald Trump led attendees at the first Republican Midterm Convention on Thursday to pledge allegiance to him and commit to voting in the November midterm elections.

Trump instructed the crowd to raise their right hands and vow: "I will go out with my family, my friends, I'll do it any way — I don't care if I'm registered or not, I'm going to try to cheat like hell like they do, and we are going to vote on November 3."

Trump then joked with attendees about the stakes. "You know what happens if you don't vote right?" he asked, answering himself: "You go to hell." The remark drew laughter from the audience.

Democrats quickly attacked the spectacle. The party's rapid response account called the pledge a "cult ritual." Tim Hogan, a Democratic messaging adviser, dismissed the entire convention as "a stunningly pointless exercise for the Republicans."

Trump's address lasted less than half an hour, a sharp contrast to the nearly two-hour speech he delivered the previous night.

Vice President JD Vance delivered a 40-minute keynote speech that was closely watched as a potential preview for a future presidential run. Vance has not publicly said whether he will seek the White House, and Trump has not named a successor. The crowd at the American Airlines Center erupted in "JD! JD!" chants when Vance took the stage.

Vance focused his remarks on affordability, border security and defending the nuclear family—core Republican themes. His speech was interrupted by a heckler waving a Mexican flag while screaming "Free Palestine." Video showed the man displaying a Mexican flag, then pulling a Palestinian flag from his pocket and throwing both toward the crowd.

Vance addressed the disruption directly. "What the people at home missed is that we just had a protester interrupting us and waving the Mexican flag," he told the audience. He then turned to the heckler: "Well, my friend, if you love Mexico so much, get your ass over there. I'll buy you a plane ticket."

The exchange ignited the crowd, which began chanting "USA." It was the most energetic moment of what had been a largely conventional political speech.