Nevertheless, my friends on the right currently fretting about potentially drastic cuts at the Pentagon need to look at that poor 19-year-old woman’s wedding to her cousin rapist and ponder what it represents: in Afghanistan, the problem is not that we have spent insufficient money but that so much of it has been entirely wasted.

History will be devastating in its indictment of us for our squandering of the “unipolar” moment. During those two decades, a China flush with American dollars has gobbled up global resources, a reassertive Islam has used American military protection to advance its theocratic ambitions, the Mullahs in Tehran are going nuclear knowing we lack the will to stop them, and even Russia is back in the game of geopolitical mischief-making.

We are responsible for 43% of the planet’s military spending. But if you spend on that scale without any strategic clarity or hardheaded calculation of your national interest it is ultimately as decadent and useless as throwing money at Solyndra or ObamaCare or any of the other domestic follies. A post-prosperity America will mean perforce a shrunken presence on the global stage. And we will not like the world we leave behind.