We all know theoretically that “sunk costs are sunk,” but when those costs are friends and teammates, it isn’t easy to walk away. There’s no way ever to quantify the loss of over 2,200 American servicemen and women, 3,800 American contractors, and 100,000 Afghans over two decades. The stoic philosophers like Epictetus and Aurelius taught to detach without being vacuous but that isn’t always the easiest advice to follow. Like all SEALs and service members of my era, I’ve buried far too many friends. We best honor them by making a stoic and intelligent choice today, not by sacrificing and investing more in a mission no longer central to our national security.