The Bush administration's surveillance policy has failed to make a dent in the war against al Qaeda. U.S. law enforcement sources said that more than four years of surveillance by the National Security Agency has failed to capture any high-level al Qaeda operative in the United States. They said al Qaeda insurgents have long stopped using the phones and even computers to relay messages. Instead, they employ couriers. "They have been way ahead of us in communications security," a law enforcement source said. "At most, we have caught some riff-raff. But the heavies remain free and we believe some of...