There is almost no chance that the ISAF (and jeebus knows my dick gets granite-hard at the limitless ocean of sometimes recursive acronyms that the modern military is truly all about) will be more than minimally "successful," by whatever no-doubt-shifting criteria they choose to measure that. There's probably a variety of reasons, some of them measurable within the overall expenditure in question.
Maybe some of the Afghan Forces trainees are Taliban saboteurs. Maybe some of the money gets siphoned off here and there to grease the palms of local warlords, or Karzai and his family. Maybe all of the above. One thing Afghanistan -- like any other collection of human beings, but two generations of war has amplified it there -- has no shortage of is pelf and power and venomous shitheads who would fuck their own country over for a fistful of dollars.
So let's say that you, Tonstant Weader, are the preznit of these here Yewnighted States, and have a fine degree from Harvard Law but zero military experience. And Stan McChrystal or Peaches Petraeus tells you that the most efficient way to kill American enemies without endangering American soldiers is to deploy a fleet of killbots high above the Hindu Kush, controlled by some guy with a joystick in a trailer in Tampa.
Sure, there's always the chance that the hellfire you rain will kill some people who already want to kill you. But you won't have to send in more troops. That's the choice being presented to you, the president, by people who have a lifetime of experience with this shit. You can't tell them no without a better plan, one that you can take to the press and try to convince millions of people who hate you on a deeply personal level.
Or they tell you that these special military programs operating halfway around the world in an extraordinarily problematic part of the world, likely run by their handpicked protégés, need to remain classified because too much information would undo all the good work they've done, and intend to do. Knowledge is power, and in this case would empower the bad guys.
So what are you gonna do, smart guy? Tick-tock, you have to make a call, and soon, because as the song says, choosing not to decide still counts as a choice.
I'm not in any respect sticking up for Obama or his chickenshit acquiescence to many of these policies, which have only increased in scale and degree, and will only continue to do so. We'll know we're at the saturation point when drones are used to attack (don't worry, it'll be spun in the media as "defending" against thuggery) the next Ferguson riot. But in the meantime, it's not that difficult to see how these wrong-headed decisions get made.