Trying to give legal legitimacy to Kurdish enclaves, has nothing to do with ISIS. What is there to gain from investing heavily into the Kurds? They are used for several main reasons:
1. Sell Iraqi oil to Israel
2. Declare northern Syria Western territory, prevent Syria from functioning as a state, put pressure on regime
3. Use as playing card against Turkey, whenever migrant talks take place, or pressure regime change in Turkey
4. Use as military base against Iran & Hezbollah in the region
5. Everyone(Assyrian, Arab, Turkmen, etc....) culture gets destroyed, except the Kurds. There is no longer a 'Syrian people', the media pretends they don't exist. All Westerners know of are 'Kurdish people', and probably end up believing all Syrians are Kurds.
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All the governments involved in this quagmire are playing very dirty games, it's just some are in better position to do so. There is no government that will arise to meet demands of the general people as a whole. The only people that came out of this slightly well, are the Egyptians IMO. Tunisia still has a way to go. Algeria managed to evade the whole thing. Saudi Arabia and Iran got further entrenched, Syrians broke down, Lebanese are on their heels, Palestinians going through drawn out status quo, etc....