Editor's Note: This article has been updated with comments from Defense Secretary Robert Gates. William Lynn's nomination to be deputy defense secretary hit a snag today when a key lawmaker raised questions about the ability of the former Raytheon executive -- who was also a registered lobbyist for the defense giant -- to execute the high-level Pentagon post and still abide by new ethics guidelines issued yesterday by the White House. Sen. Carl Levin (D-MI), chairman of the Senate Armed...