WASHINGTON - Health and Human Services Secretary Tommy Thompson resigned Friday, The Associated Press learned, broadening an exodus that has emptied more than half of President Bush's Cabinet before he takes the oath of office for a second term. Thompson submitted his resignation to Bush, and planned to announce his departure at a Friday afternoon news conference, said an official close to the former Wisconsin governor who asked not to be identified. Mark McClellan, the government's Medicare chief and brother of White House press secretary Scott McClellan, is Thompson's likely successor, officials said. Thompson's resignation brings to eight the number...