After thirteen years of war, the loss of many thousand of lives, and the expenditure of trillions of dollars, what has the United States learned? The answer depends on not only who is asking but when. The story of the Iraq war would have different endings, and morals, if told in 2003, 2006, 2011, or 2014, and it will continue to evolve. As for Afghanistan, the narrative there has also shifted over time, and the ending also remains in doubt. Neither disaster has been unmitigated. But few would argue that Washington’s approach to either has been a success worth emulating. So the most important question today is what can be learned from the failures.