America was born in the shadow of shadow wars. In Conquered into Liberty, Eliot Cohen recalls the “Great Warpath” — the corridor from Montreal to Albany where armies battled over the course of centuries. Even then, warfare included what we call today “black operations.” But, as Cohen notes, these missions, “particularly those that are the stuff of legend, rarely actually accomplish all that their publicists (including themselves) promise.”

In part, he concludes, the conflict on the Great Warpath spanned generations because black ops tactics can’t, by themselves, achieve a decisive conclusion.