Simon: Well, I disagree with you on Afghanistan because at the time this was where Bin Laden was located and Al Queda had it's headquartered. They even got a choice: Hand over Bin Laden or face the consequences. They choose the consequences.
I must admit I didn't study the Libya conflict closely, so I am not very familiar with the story. From what I know, the story is about how weapons for Libyan rebels made it to Syria?
Can we agree that getting rid of Ghadaffi was a good thing?
Re. ISIS, no, I support vetting of refugees and very harsh punishment for western sympathizers who travel to Syria. I think per default a person who travel to Syria understands he will participate in warcrimes and crimes against humanity and his prison sentence should reflect that.
As I understand the situation, there is little evidence ISIS is sending terrorists to the west to perform acts of terror, because ISIS is still focused on the Kaliphat (I might be wrong). If you got evidence to the contrary I would be interested in seeing it. (I did my reading on ISIS 6 months - 1 year ago and things might have changed).