We ought to realize by now (see Korea, see Vietnam, see Afghanistan, see Iraq, see Iran) that deploying the US military, or dealing billions of dollars a year of arms to our ally of the moment that can serve as a regional rival to our enemy of the moment, is not always the best way to make threats go away. Our military and weapons prowess is a fantastic and perfectly weighted hammer, but that doesn't make every international problem a nail.

Drift: The Unmooring of American Military Power (ed. Broadway Books, 2012) - ISBN: 9780307461001