James Mattis was an unusual choice for secretary of defense, an explicitly civilian role. It wasn’t so long ago that Mattis was the commander of Centcom, America’s sprawling military presence in the Middle East and Central Asia. Sure enough, there was a widespread sense in the Pentagon that Mattis was more inclined to trust senior military officials, many of whom he came to know over the course of his decades-long career as a Marine officer, than the senior civilian officials charged with overseeing uniformed personnel.
Given the importance of civilian control over the military, one might expect Mattis’s unorthodox approach to leading the Pentagon to have raised concerns among leading members of the national-security community. But it did not, for the simple reason that in contrast to President Donald Trump, whom he served only with great ambivalence, Mattis firmly adhered to the bipartisan internationalist consensus on foreign and defense policy. It is therefore not surprising that his departure has set off a panicked reaction.
Particularly at the start of the Trump presidency, Mattis was a reassuring figure. He was living proof that despite Trump’s seemingly endless series of provocations, U.S.-led alliances would remain intact, and indeed might be strengthened. Consider that though the president has loudly and persistently questioned the wisdom of the U.S. commitment to the defense of its European allies, U.S. military spending in Europe has increased from $789 million to $4.77 billion during his tenure, with more expected to come. This was very much Mattis’s handiwork, as was the Pentagon’s new National Defense Strategy, which called for a greater emphasis on great-power competition and meeting the challenge posed by a revisionist China.