The US had no legal or moral basis for being in Syria in the first place, and now it has no legal or moral basis for taking Syria’s oil. US foreign policy is for the most characterized by actions that have no legal or moral basis. From Pepe Escobar at thesaker.is:
Compare US pillaging with Russia-Iran-Turkey’s active involvement in a political solution to normalize Syria

What happened in Geneva this Wednesday, in terms of finally bringing peace to Syria, could not be more significant: the first session of the Syrian Constitutional Committee.
The Syrian Constitutional Committee sprang out of a resolution passed in January 2018 in Sochi, Russia, by a body called the Syrian National Dialogue Congress.
The 150-strong committee breaks down as 50 members of the Syrian opposition, 50 representing the government in Damascus and 50 representatives of civil society. Each group named 15 experts for the meetings in Geneva, held behind closed doors.
This development is a direct consequence of the laborious Astana process – articulated by Russia, Iran and Turkey. Essential initial input came from former UN Envoy for Syria Staffan de Mistura. Now UN Special Envoy for Syria Geir Pedersen is working as a sort of mediator.
The committee started its deliberations in Geneva in early 2019.
Crucially, there are no senior members of the administration in Damascus nor from the opposition – apart from Ahmed Farouk Arnus, who is a low-ranking diplomat with the Syrian Foreign Ministry.