It is hardly remarkable to say that success for the United States in Afghanistan was never likely. For years, experts, scholars, and officials have coalesced on a common set of causes for failure—local grievances, political factionalism, corruption, Pakistani safe havens, and a deep-seated Afghan resistance to occupation. All are notoriously intractable. The difficulty of changing the course of the Afghan war begs the question why the United States didn’t just leave and curtail the expense.