“I loooove to pick on the Saudis,” the South Carolina trial lawyer Ronald Motley said in a 2004 New York Times magazine cover story, “A Nation Unto Himself.”

The U.S. executive and judiciary are less eager to tweak the House of Saud. But Motley’s trillion-dollar 2002 claim against the Kingdom, captioned In re Terrorist Attacks on September 11, 2001, has experienced a slow-motion revival that culminated last month in the quiet filing of a devastating new complaint. The Sept. 15 amended complaint, filed by the late Motley’s more sober cocounsel at Cozen O’Connor, only seeks some $200 billion for Saudia Arabia’s alleged role in backing the 9/11 terrorists. The lively, 156-page narrative reads as a prequel to the 9/11 Commission Report, and as a much-needed corrective.