(I'm going to take sh**t for this one)
Let me start by saying I DO NOT ADVOCATE THIS POSITION, but, playing devil's advocate here, Afghanistan did, it can be argued, go a long way towards hastening the Soviet Union's financial collapse. Iran's economy is in the toilet.
Alright, I'll jump in so you don't have to. Though I don't actually believe Afghanistan was a huge, or even a significant factor in the economic woes of the Soviet Union.
Even in retrospect, supporting the Mujahedin was the correct choice. The vast majority of the Muhajedin groups we supported do not engage in violent activities against the United States. The Taliban was only one of many factions. A faction that is often at violent odds with the other factions that comprised the vast majority of the Mujahedin. And Al-Qaeda was really a non-player in the anti-Soviet resistance.
And about aid flowing to some people who might become future enemies...well, I don't hear anyone complaining about Lend-Lease.
No clue about the Syria rebel arms thing though. This area of the world has never been my area of expertise and the situation on the ground changes too often and is too poorly understood for me to really direct US policy or anything ridiculous. It's something very difficult from already well-understood history (eg. the Soviet Invasion of Afghanistan)
