President-elect Donald Trump recently named retired U.S. Marine Corps General James Mattis as the new secretary of defense. Referred to as “Mad Dog,” Mattis is beloved by rank-and-file military personnel, military personnel, think tank analysts, and the media. But questions remain about what he will bring to the Pentagon. The job of secretary of defense, as the subtitle of a book on the subject by Charles A. Stevenson suggests, is “nearly impossible.” In fact, as Stevenson writes, it is actually four jobs: manager of the Pentagon, war planner, diplomat, and National Security Council (NSC) advisor. Taking each in turn might be helpful in understanding why Mad Dog might appeal to Donald Trump and how he might approach his job when confirmed.

The first, and most important, job of a secretary of defense is to manage the world’s largest bureaucracy. It is unclear at this point what General Mattis would bring to that job. Much has been made about the fact that legislation will be necessary for Mattis to be confirmed as secretary of defense given existing legal prohibitions against general officers serving in the position for at least seven years after their retirement. The last retired general to do so was the legendary George C. Marshall. However, Marshall’s specialty was in organizational matters—with Winston Churchill dubbing him after World War II the “Organizer of Victory.” Mattis, on the other hand, is most famous for being a combat general.

Attempts to manage the Pentagon, both those that fail and the few successes, have a lasting legacy. As written here ad nauseum, the Department of Defense still operates according to managerial practices installed over half a century ago by Robert McNamara. Because he was a field commander, there is little information about how Secretary of Defense Mattis will manage multiple military services, relations with Congress, an unruly bureaucracy, and procurement programs experiencing cost overruns and schedule delays. As Erin Simpson, a well-known defense analyst and Mattis fan writes at War on the Rocks, “Warfighters rarely make good bureaucrats. The Pentagon is one of the world’s largest bureaucracies, and Mattis has shown little patience for management and administration.”

The second job of a secretary of defense is, according to Stevenson, being a war planner. Here Mattis may be more suited to the post given his extensive, and widely praised, combat experience. It is also this qualification that helps explains President-elect Donald Trump’s interest in him. Based on a number of his most famous quotes, Mattis seems to have a similar “Jacksonian” sensibility to that of his future boss. As Walter Russell Mead—the historian who developed the term as a school of foreign policy thinking—suggests, Jacksonians do not seek war, but are willing to be utterly ruthless in pursuit of victory when once it’s initiated.

Jacksonians are brawlers, and Mattis has famously said brawling is something he enjoys. In regard to fighting the Taliban in Afghanistan, he once said, “Actually it’s quite fun to fight them, you know. It’s a hell of a hoot. It’s fun to shoot some people. I’ll be right up there with you. I like brawling.” But in Mead’s telling, while Jacksonians are happy to brawl, they usually won’t do so unless provoked. And one of Mattis’ most famous quotes captures that sentiment: “I come in peace. I didn’t bring artillery. But I’m pleading with you, with tears in my eyes: If you f*** with me, I’ll kill you all.”

Such a sentiment fits neatly within the Jacksonian war doctrine Mead describes. And a willingness to use overwhelming military force is something the president-elect has demonstrated a desire for, saying on the campaign trail that he would “bomb the sh*t” out of the Islamic State if elected. If Mattis, in his role as war planner, is willing to use force overwhelmingly when he employs it, then it goes a long way to explaining why—outside of his popularity—Trump was attracted to having him as secretary of defense. However, as will be discussed shortly, there are also important differences on this front between the soon-to-be secretary of defense and commander-in-chief.

First though, there is a third job the secretary of defense must fulfill: that of a diplomat. While he is most famous as a combat general, Mattis also served as the Combatant Commander for the military Central Command (CENTCOM). Combatant commanders are often described as either “viceroys” or “proconsuls,” given the resources they command and authority they have within their areas of responsibility. Despite his reputation as a warrior, diplomacy will therefore not be an area in which Mattis lacks experience. Thus far, feedback from American allies—alliances Mattis has argued are necessary despite his future boss’ skepticism during the campaign—has been generally positive.

Finally, according to Stevenson, the secretary of defense must act as an advisor to the National Security Council. It is in this capacity where the differences between Mattis and Trump might come into play. Though they might hold similar Jacksonian sentiments, the president-elect’s thin skin and anti-intellectualism are a stark contrast to the man he has appointed to be his secretary of defense. While he may be a brawler, Mattis has also been described as a “warrior monk.” He is a thoughtful intellectual. In the wake of his appointment as secretary of defense, a leaked email he sent before deploying to Iraq has made the rounds on the internet. In it, Mattis describes why reading and studying history are of vital importance to those ordering men and women into combat. Writing to a colleague in 2004, he said:

By reading, you learn through others’ experiences, generally a better way to do business, especially in our line of work where the consequences of incompetence are so final for young men.


Thanks to my reading, I have never been caught flat-footed by any situation, never at a loss for how any problem has been addressed (successfully or unsuccessfully) before. It doesn’t give me all the answers, but it lights what is often a dark path ahead.

The whole thing is worth reading and speaks to the type of counsel Mattis might give to a President Trump as an advisor to his NSC. And while Trump might have seen another Jacksonian “brawler” in Mattis, the latter is more nuanced in his thinking about modern warfare:

We can’t adopt one preclusive kind of warfare because the enemy always moves toward your perceived weakness. So, it’s how do we maintain — assuming we don’t break the bank — safe nuclear deterrents, so that those weapons are never used? How do you maintain a decisive conventional force with the changing character of war, and still make your regular warfare a core competency? Which is mostly an intellectual adaptation.


So you define the problem to a Jesuit’s level of satisfaction — and then it’s a lot easier to get everybody on board. As Einstein said, ‘Given an hour to save the world, how would he compose his thoughts? Fifty-five minutes to define the problem; save the world in five.’ We’re not defining the problem in a way that brings the body politic or defines the elements and start doing what we know how to do. There’s enough examples.

Moreover, Mattis has in the past disagreed with Trump about building a border wall, banning Muslims from entering the United States, and NATO’s obsolescence. In their face-to-face meeting, Mattis also told Trump that he thinks torture is ineffective.

Mattis is no dove. He is in fact quite hawkish on the subject of Iran. However, all available evidence suggests that he is someone who has put thought behind the why, when, where, and how of the use of force. That is an important quality to possess given the volatility of the next commander-in-chief, as well as the man who will run the NSC as national security advisory: retired U.S. Army Lieutenant General Michael Flynn. As opposed to the thoughtful approach Mattis describes in his 2004 email, recent reporting suggests that Flynn’s approach to analyzing the world is one that flatters his ego and conforms to his own worldview—and a bizarre worldview at that.

While managing the Pentagon might be the most important role for most secretaries of defense, for Mattis his most important function might be to advise the NSC. As the chief advisory body to the president on national security, the NSC is where foreign policy is made. The question will be: who in that body gets this president’s ear? Will it be a thoughtful warrior such as Mattis? Or a paranoid egomaniac such as Flynn?