But if the president has been everything his skeptics feared, Defense Secretary Jim Mattis has been everything they could have wished for.

When Mattis was tapped by Trump, liberals and conservatives alike hoped the retired Marine Corps general and former commander of U.S. Central Command would live down his Mad Dog sobriquet and be a sober counterweight to an erratic president. Elliot Cohen, a foreign policy expert and one of Trump’s loudest conservative critics, said the general “would be a stabilizing and moderating force, preventing wildly stupid, dangerous, or illegal things from happening.” The Senate agreed. After an impressive hearing in which Mattis committed to existing alliances and strongly disapproved of Russian President Vladimir Putin, he was overwhelmingly confirmed by Congress’ upper body, 98-1. He even received a “we’re counting on you” from fierce Trump critic Sen. Elizabeth Warren (D-Mass.).

So far, that trust has not been misplaced. Mattis has already proved an effective foil to some of Trump’s worst instincts.