(White House/Pete Souza)

Hours before dawn on one of the last days of October 2009, the deadliest month for American troops in Afghanistan since 2001, Eric Holder, attorney general of the United States, strode out of a C-17 cargo plane parked at Dover Air Force Base in Delaware. President Barack Obama, having reversed the ban on media coverage of the arrival of war dead at Dover, trailed just behind. During the official military ceremony, the two friends stood in dark suits, silently saluting 18 servicemen, including three Drug Enforcement Agency officials claimed by the Afghan War days prior. The aggrieved expressions on their faces were identical.

Holder's presence was surprising. The attorney general has played only a minor role in the public...