Lt. Gen. Dan Caine, a relatively unknown figure, replaced Gen. C.Q. Brown as chairman of the Joint Chiefs in a Friday night upheaval at the Pentagon directed by Defense Sec. Pete Hegseth.

The air traffic control tower at Ronald Reagan Washington National Airport is pictured, Friday, Jan. 31, 2025, in Arlington, Va., near the wreckage of a mid-air collision between a Black Hawk ...