In the case of McMaster, administration officials tell me he is perceived not to be a reliable messenger of the president’s wishes. What’s more, administration figures tell me, principals including Tillerson, Mattis and CIA director Mike Pompeo have a direct line to Trump. They can go around McMaster and make their case on interagency disputes directly to the commander in chief.

For a national security adviser, this dynamic is deadly. Traditionally, this job is supposed to coordinate policy throughout the government to meet the directives of the president. That job is next to impossible if the adviser isn’t seen as speaking for the president. While all administrations experience infighting, rarely has a national security adviser been this weak…

McMaster has also clashed with Tom Bossert, the assistant to the president for homeland security and counterterrorism. On the organization chart for the White House, Bossert reports directly to Trump. He has key NSC directorates report to him as well, though Bossert and McMaster share responsibilities on counterterrorism. At the last minute, McMaster tried to cancel a trip Bossert took in June to Israel to address a cybersecurity forum, reflecting concerns from other department heads that NSC staffers were overstepping their roles in foreign travel. McMaster eventually withdrew his objections, and Bossert attended the conference in Tel Aviv.