Rex Tillerson’s relationship with President Trump was rocky from the start. But no one was more surprised than Mr. Tillerson when he was fired as secretary of state on Tuesday. Mr. Tillerson was the most persistent advocate of opening diplomatic channels with North Korea, a position that put him publicly at odds with his boss. As Mr. Trump prepares to meet Kim Jong-un, the North’s leader, we talk to the man who came closest to a deal with Pyongyang about what the current administration can learn from previous attempts. Guests: Mark Landler, a White House correspondent for The New York Times; William Perry, a former secretary of defense and one of the few senior U.S. officials to have negotiated directly with the North Koreans. For more information on today’s episode, visit nytimes.com/thedaily.