Military prosecutors dropped charges against a Marine sergeant accused in the death of a fellow Marine forgotten in the Southern California desert because the officer who convened the sergeant’s court-martial was relieved of duty for his role in the incident. Defense attorneys argued that battalion commander Lt. Col. Edward J. Robeson’s “personal interest in the case would hamper the impartiality of the trial” in which Sgt. Christopher Clyde was charged with dereliction of duty and disobeying orders. Lance Cpl. Jason J. Rother, 19, of Minneapolis, died last August of apparent dehydration in the Mojave Desert. The charges against Clyde have been referred to higher authority outside Robeson’s battalion and Marine Corps officials said they expect a new court-martial to be ordered.