Efforts to negotiate an end to the war in Iran hit a major roadblock Saturday as President Donald Trump abruptly canceled a high-stakes trip to Pakistan for U.S. negotiators. The decision has left the future of the Pakistan-mediated peace process in doubt and signals a deepening impasse between Washington and Tehran. President Trump called off the mission for Special Envoy Steve Witkoff and Jared Kushner, who were scheduled to fly to Islamabad on Saturday morning for a second round of direct negotiations.