He opposed Trump’s decision to withdraw from the Paris climate change accord, decertify the Iran deal, slap tariffs on steel and aluminum, and move the U.S. Embassy in Israel from Tel Aviv to Jerusalem. He opposes the president’s proposed ban on transgender service members and has reportedly ignored requests from the White House to see plans for a military strike against North Korea.

Yet Mattis has been able to present the president with views he doesn’t like without bearing the brunt of his frustration.