Sign up for the daily CJR newsletter. At 2:30am ET on Saturday, Donald Trump posted a video on Truth Social—the social media platform he owns and uses for fleeting thoughts, administration propaganda, and policy announcements—in which he said that “major combat operations” were underway in Iran. About fifty minutes earlier, Reuters and the Associated Press had reported on witnesses in Tehran, the capital, hearing explosions and seeing thick smoke rise into the sky. Residents were described as running in the streets in panic. For about half an hour, reports circulated that Israel was attacking Iran, until the New York Times clarified that the US was also involved, citing a US official.…