Jonathan Chait: “On Monday morning, CNN reported that the United States and Iran had been on the verge of striking a deal to end the war when Donald Trump made a series of comments to reporters and on social media that undermined the talks.”Said one White House source: “The Iranians didn’t appreciate POTUS negotiating through social media and making it appear as if they had signed off on issues they hadn’t yet agreed to, and ones that aren’t popular with their people back home.”“This was Trump’s signal to begin binge-posting about the Iran negotiations. The Iranians may not have appreciated Trump’s stream-of-consciousness messaging, and apparently their American counterparts did not either. But one very important person did.”