Train thy enemy
Those 300,000 Afghani soldiers weren't our allies, they were just learning how to be better soldiers against imperial invaders for the next time a superpower forgets history and decides to again attempt to tame the Graveyard of Empiresâ„¢ (Last time, got training by both Spetsnaz and the Green Berets. This time, the Navy Seals!) That'll show the next invading army!