The clandestine U.S. commandos whose job is to capture or kill Osama bin Laden have not received a credible lead in more than two years. Nothing from the vast U.S. intelligence world — no tips from informants, no snippets from electronic intercepts, no points on any satellite image — has led them anywhere near the al-Qaeda leader, according to U.S. and Pakistani officials. "The handful of assets we have have given us nothing close to real-time intelligence" that could have led to his capture, said one counterterrorism official, who said the trail, despite the most extensive manhunt in U.S. history,...