For example: The Taliban bomber calmly parked a white fuel tanker near the prison gates of this city one evening in June, then jumped down from the cab and let out a laugh. Prison guards fired on the bomber as he ran off, but they missed, instead killing the son of a local shopkeeper, Muhammad Daoud, who watched the scene unfold from across the street. Seconds later, the Taliban fired a rocket-propelled grenade into the tanker, setting off an explosion that killed the prison guards, destroyed nearby buildings, and opened a breach in the prison walls as wide as a highway. Nearly 900 prisoners escaped, 350 of them members of the Taliban, in one of the worst security lapses in Afghanistan in the six years since the United States intervention here. The prison break, on June 13, was a spectacular propaganda coup for the Taliban not only in freeing their comrades and flaunting their strength, but also in exposing the catastrophic weakness of the Afghan government, its army and the police, as...