With the likely (Trump as uncertainty engine raises doubts about his own statements) appointment of General (ret.) Mattis as Secretary of Defense and perhaps several other retired generals in his administration, people are wondering if this is a good idea or not. Count me in on the NOT! side of the argument.
Sure, retired generals know about management and leadership since the military spends far more time thinking about how to manage their people than they do thinking about firing a gun, dropping a bomb or launching a torpedo. And, yes, getting to the top of a very competitive in-or-out promotion process means that these folks have been vetted and vetted again (just ignore the Tommy Franks problem* for moment). So, let's concede for a moment that Mattis is a really sharp guy, who has probably deserved the cult of personality that has grown up around him.
While some dismiss the importance of civilian control of the military, I find it to be a central ingredient, a necessary condition of this thing we call democracy. Contra to Rosa Brooks, civilian control of the military is both means and end. It is not just about concentrations of power, but of subservience of the folks with the guns to the people elected to run the country. This is not about the founders of the US or about what makes the US special, but what is essential for modern democracy.
Brooks argues that the US military has its own internal checks against seizing power or being disobedient. She combines this with an assertion that Trump's presidency presents all kinds of threats that make civilian control of the military far from being a priority. And there is the rub: Trump's inherent flaws, including his appeals to white supremacy, his inability to concentrate for the length of an intel briefing, and, most importantly, his lack of respect for and adherence to the various norms that make the institutions operate, make civilian control of the military more, not less, important.
Coups happen for a variety of reasons, but most often, those engaged in a coup claim that the government is corrupt and/or incompetent. Here is where I could insert a picture of Trump. Trump called Taiwan's President perhaps to facilitate his own business interests, which is an abuse of power that could be called a coup excuse (my thinking of coup politics is heavily shaped by Junta, the game). This is not a one-off thing given that Trump brought up his business interests in Argentina during his phone call with that leader as well.
Simply put, when many of the norms and institutions are under attack, we need to be more, not less, careful about the role of the military in our society. It is, of course, not so much about coups (the first generation of civil-military relations thinking--Huntington, Finer, Luttwak, Janowitz), but about controlling the military so it does what the civilians want (second generation--Feaver**, Avant) and about getting the military to work well with civilian agencies in "whole of government efforts (the third generation). Getting any complex agency to follow orders is hard (Trump is going to make principal-agency so trendy), but especially one that largely lives apart from society, that tends to attract leadership from only a small portion of the country, that socializes so very powerfully, and is also one of the few institutions that is highly esteemed these days.
There was a good reason why the legislators thought a ten year (revised downwards to seven) wait was required for retired military officers to serve as Secretary of Defense. Time away from the military to broaden one's imagination, be exposed to civilian norms of decision-making and leadership and on and on. The limit of officers serving immediately after retirement is not an accident but a good policy that should not be tossed away simply because Trump admires generals (sort of).
In a time where authoritarian politics (threats towards journalists and protesters, etc) are increasing popular, we should put the US military, active and retired, further away from the controls of the US government, not closer.
* One way to move up is to kiss up, kick down. Not a great way to lead. Plus there is the Peter principle--being promoted beyond one's abilities. So, the existence of a four star general like Tommy Franks, who was engaged in a serious competition for the dumbest @#$*& in DC with Doug Feith, undercuts just a bit the argument that promotion to the top means that these folks are well vetted.
** See Feaver's review piece of the latest civ-mil work.