What does it mean to be an “adult” in Washington in general, or, in particular, under Donald Trump? What policies do the “adults” favor? Where do they come from, and what do they believe? Most importantly, what is the significance of the fact that most of Trump’s so-called grownups come from the military? To answer such questions, it helps to look at the history, both of the way the idea of “adults” has been used in Washington in the past and of the way military officers in the US have served in top civilian jobs.