The key to understanding the calamitous Afghan war is the complex, ultimately failed relationship between the powerful, duplicitous Karzai family and the United States, brilliantly portrayed here by the former Kabul bureau chief for The Washington Post.

The United States went to Afghanistan on a simple mission: avenge the September 11 attacks and drive the Taliban from power. This took less than two months. Over the course of the next decade, the ensuing fight for power and money--supplied to one of the poorest nations on earth, in ever-greater amounts--left the...