The U.S. Marine Corps is without a confirmed leader for the first time in a century as Gen. David Berger stepped down as commandant on Monday and a Republican senator is blocking approval of his successor. Berger took over as the 38th commandant in July 2019, and is required to leave the job after four years. Gen. Eric Smith, currently the assistant commandant, has been nominated to be the next leader, but will serve in an acting capacity because he hasn't been confirmed by the Senate.