The United States and Iran are crossing each other's red lines, one after the other. The latest hostilities began with an Iranian drone attack on a cargo ship in the Strait of Hormuz on June 25, a week after they had signed an interim deal aimed at ending the war. Iran claims that agreement gave it the right to manage traffic through the strait, while the U.S. and others say it should be fully reopened. Iran's attacks on shipping have since led to U.S. airstrikes, Iranian retaliation against Gulf states and the collapse of the agreement. A return to full-scale war appears increasingly likely.