Twenty-seven years old and growing older by the day, AFM 2-1 became technically obsolete and largely irrelevant in the early 1980s as doctrinal guidance for the employment of airpower at the operational level of war. In response to a rapid onset of contextual and technological change, a body of informal doctrine grew to fill this doctrinal gap between practice and published guidance. In the opening weeks of the Persian Gulf crisis, the USAF's reliance on informal doctrine to guide operational airpower employment had the adverse consequences of introducing unwanted fog and friction into the air campaign planning process. Nonetheless, the USAF's largest test of the operational employment of airpower since the Vietnam War -- Operation DESERT STORM -- ended in resounding success. Following the conclusion of the Gulf War, theater-level airpower employment has received much attention in joint doctrine manuals and USAF publications. This guidance has served to largely "close the gap" between practice and doctrine regarding the operational employment of airpower.