President-Elect Donald Trump has selected retired Marine Corps Gen. James N. Mattis to serve as Secretary of Defense. Mattis retired from active duty in 2013 after serving as chief of U.S. Central Command. Trump will ask Congress to waive the law that requires former service members to be out of uniform for at least seven years before assuming civilian government posts. The outgoing administration reacted warmly to Mattis’ nomination. “I have known Gen. Jim Mattis for many years and hold him in the highest regard,” said Secretary of Defense Ash Carter. “I will continue to do everything I can to help ensure a seamless transition at the Department of Defense,” he said.