Generally speaking, the Syrian government and the YPG liberated the territories lying west and east of Euphrates respectively. Everyone did his part in eliminating ISIL, with the Iraqi regular army and the various militias dedicating the largest number of resources, in order to recapture the most important strongholds of the terrorist group. Arguing which foreign power attacked ISIL more decisively is rather futile, as such a question cannot be measured objectively, it does not take into account each state's relative strength and wealth and it also loses the main point of the international intervention, which is the common victory against one of the most bloodthirsty and sectarian groups that ever emerged in the Fertile Crescent.