NEW ORLEANS - A Barack Obama impersonator was ushered off the stage after he mocked the Republican presidential hopefuls and joked about the real president's biracial roots to a room full of conservative activists Saturday. The Republican Leadership Conference turned the podium over to impersonator Reggie Brown, who drew raucous applause from the GOP's supporters when he projected lewd photos of Rep. Anthony Weiner, the New York Democrat who just resigned after the furor over his sexually charged online dalliances with a former porn actress and other women. Brown later played up the mass exodus of advisers to candidate Newt...