The case of Khaled el-Masri is the most extensively documented case of what's called "extraordinary rendition." The CIA is accused of seizing terrorists and transporting them to countries known to use torture in their interrogations. When it refused to take el-Masri's case, the Fourth US Circuit Court of Appeals said, "We recognize the gravity of our conclusions." It explained that the case "pits the judiciary's search for truth against the executive's duty to maintain the nation's security." Today the US Supreme Court turned down el-Masri's appeal. Dahlia Lithwick is senior editor at Slate and a contributor to NPR's Day to Day.