Trump decided hastily to remove Mattis in reaction to negative news coverage, according to senior administration officials, one of whom said the president was eager to retaliate against Mattis and show up the widely respected former general. Another official said Trump and other advisers suspected Mattis of being part of a campaign to stoke negative coverage about the president.

After canceling his Christmas trip to Florida in view of the government shutdown, Trump was marooned this weekend at the White House watching hours of cable television news shows. Advisers said he stewed over commentary hailing Mattis as heroic — a human guardrail against the president’s impulses.

Trump was so angry with Mattis that on Sunday morning he directed Secretary of State Mike Pompeo to inform the defense secretary that he was being pulled from office two months early, according to a senior administration official.