Jim Mattis

Jim Mattis, who resigned as Trump's defense secretary nearly a year and a half ago, accuses the president of dividing the nation and warns against "militarizing our response" to protests.

Deputy Defense Secretary Patrick Shanahan will assume Mattis' duties starting in the new year. Trump had previously said Mattis would step down at the end of February.

The retired Marine general had been granted a rare waiver to run the Pentagon as he had been out of uniform for only three years, but his relationship with President Trump eventually turned cold.

Defense Secretary Jim Mattis is leaving an Obama-era policy on transgender military service members largely intact, saying he needs input from an expert panel.