Defense Secretary James Mattis announced his retirement last week, explaining he would officially leave his post at the end of February to ensure a smooth transition of power at the Pentagon.
But President Donald Trump decided over the weekend Mattis needed to be replaced immediately.
What are the details?
Trump announced Sunday that Deputy Defense Secretary Patrick Shanahan will assume the role of acting secretary of defense on Jan. 1, 2019. He will officially receive the title of "Secretary of Defense" upon Senate confirmation.
"Patrick has a long list of accomplishments while serving as Deputy, & previously Boeing. He will be great!" Trump announced.
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
The announcement means Trump has pushed Mattis out of office a full two months prior to his planned departure.
In a resignation letter, Mattis highlighted policy differences with the White House as the impetus for his departure from the Pentagon.
"Because you have the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position," Mattis wrote.
Why did Trump remove Mattis prematurely?
While Trump's Sunday announcement may have come as a shock to some, others saw it coming.
According to a New York Times report published Sunday, Trump became "furious" over the "negative news coverage" surrounding Mattis' resignation letter, which was widely characterized as a rebuke of the Trump presidency. The media coverage, the Times reported, inspired Trump to immediately remove Mattis.