Andrew Yang has said this before, and he said it again onstage at The Wall Street Journal’s Future of Everything Festival Wednesday: He’s running for president in 2020. He also said his universal basic income plan will protect workers from the AI revolution.

Mr. Yang’s pitch has inspired a large online following that calls itself “The Yang Gang.” His plan would give $1,000 month to all adult Americans, to do with as they see fit. He called it “the most feasible, expedient massive social response” to inject spending power into...