A selection of definitions: “to decline in quality, activity, or quantity” , “to descend freely by the force of gravity” or “to suffer ruin, defeat, or failure” are applicable.
Most would prefer #3 in terms of the BATFE. Personally, I prefer #2, as in
“The fall of the ATF was similar to that of a worker named John, who was both stupid and unlucky enough to tempt gravity near the intake for an industrial meat grinder. The outcome was gruesome and produced enormous terrified screaming, but ultimately, was for the best because John was actually just like an ATF agent in that he was completely fucking useless to the point of being dangerous and also extremely annoying. Both were so despised by the citizenry that every year, on the anniversary of the fall a nationwide celebration is had to give thanks that both John and the ATF met a well deserved end.”.