Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Trump Tweets: Defense Secretary Mattis to Retire in February by Associated Press WASHINGTON -- President Donald Trump has announced that Defense Secretary Jim Mattis will retire at the end of February. Trump says on Twitter that a new secretary of defense will be named soon. Trump's announcement comes a day after he surprised U.S. allies and members of Congress by announcing the withdrawal of U.S. troops from Syria.