The 1980s was mostly a decade of reorganization. The Army converted to an all-volunteer force with greater emphasis on training and technology. The Goldwater–Nichols Act of 1986 created Unified Combatant Commands, bringing the Army together with the other three military branches under unified, geographically-organized command structures. The Army also played a role in the invasions of Grenada in 1983 (Operation Urgent Fury) and Panama in 1989 (Operation Just Cause).