President Donald Trump abruptly fired Air Force Gen. CQ Brown Jr. as chairman of the Joint Chiefs of Staff on Friday, sidelining a history-making fighter pilot and respected officer as part of a campaign led by his defense secretary to rid the military of leaders who support diversity and equity in the ranks.

The decision to fire Gen. Charles Q. Brown Jr., a four-star fighter pilot, upends a tradition in which the Joint Chiefs chairman traditionally remains in place as administrations change.