On August 28, the E3 (Britain, France and Germany) set the clock ticking, triggering the snapback mechanism and warning Iran that it must show meaningful progress on nuclear diplomacy within 30 days or face the return of pre-2015 U.N. sanctions. Coming after Israel and the United States attacked Iran, hitting nuclear facilities and infrastructure and assassinating senior Revolutionary Guard (IRGC) officers and nuclear scientists, the EU’s decision has raised the stakes immeasurably. It also...