Something along that line should be practiced.
Unfortunately, even though the Geneva Conventions allow it, we don’t seem to have the guts to execute the ‘partisans’ and bandits.
It is best though, if we just get the heck out. We have no lasting worthwhile achievements to point at in the ME. More of the same will not improve things.
Unfortunately I don’t think we can afford to step out. Leaving the field to the super vicious ISIS forces means they would eventually take over large swaths of that area and acquire nuclear weapons and have no qualms about using them.