Jim Mattis
The letter also attacks former Defense Secretary Jim Mattis for criticizing the president.
“The president has clearly forgotten how it actually happened or is confused,” Trump's former chief of staff said.
Republican lawmakers who fear reprisals from the president and his supporters reacted to Jim Mattis' letter excoriating the president in familiar ways.
"We are witnessing the consequences of three years without mature leadership," the former defense secretary wrote to The Atlantic.
WHAT'S HAPPENING
Like a wife who's the president's daughter?
The former defense secretary had a very adverse reaction to the plan, according to a new book by his former communications director.
The former defense secretary unleashed a hilarious roast on the president at the annual Alfred Smith memorial dinner.
The former defense secretary warned that national security is "tied inextricably to our alliances," following Trump's decision to abandon the Syrian Kurds.
The former defense secretary said he didn't know the former vice president would launch a bid for the White House.
The former secretary of defense has remained tight-lipped about his views of the Trump administration, saying he wouldn't speak out from "the cheap seats."