The tactical advantage of nerve gas is that it will kill the enemy without destroying infrastructure. That aside it is a weapon of little advantage so its use in Syria by government forces makes no sense! If it was used in an area where bombs and munitions would damage important government equipment there may be a reason. If you just want to kill innocent people or a perceived enemy bombs and bullets will do the job just fine! In the name of God war is justified! Methinks it's time for God to take a stand if He exists!