Deputy Defense Secretary Patrick Shanahan will assume Mattis’ duties starting in the new year. Trump had previously said that Mattis would step down at the end of February.
I am pleased to announce that our very talented Deputy Secretary of Defense, Patrick Shanahan, will assume the title of Acting Secretary of Defense starting January 1, 2019. Patrick has a long list of accomplishments while serving as Deputy, & previously Boeing. He will be great!
— Donald J. Trump (@realDonaldTrump) December 23, 2018