The US government is using Syrian oil as an excuse to stay in Syria, because it will never give up its regime change dream. From Andrea Germanos at commondreams.org:

Syrian soldiers are seen deploying in an oil-rich area in the countryside of Qamishli, northeastern Hasakah province, Syria, on Nov. 5, 2019. The Syrian army on Tuesday deployed in new areas rich in oil fields in the countryside of Hasakah province in northeastern Syria, the latest progress in the overall deployment of the Syrian army in Kurdish-held areas near the border with Turkey. (Photo: Xinhua/ via Getty Images)
Pentagon officials asserted Thursday U.S. military authority over Syrian oil fields because U.S. forces are acting under the goal of “protecting Americans from terrorist activity” and would be within their rights to shoot a representative of the Syrian government who attempted to retake control over that country’s national resource.
The comments came from Pentagon spokesperson Jonathan Hoffman and Navy Rear Admiral William D. Byrne Jr. during a press briefing in which the two men were asked repeatedly about the legal basis the U.S. is claiming to control Syrian oil fields.
The briefing came less than two weeks after Defense Secretary Mark Esper said, “That’s our mission, to secure the oil fields” in the Deir ez-Zor area of eastern Syria. President Donald Trump’s comments before and after that remark —”We’re going to be protecting [the oil], and we’ll be deciding what we’re going to do with it in the future,” and “The oil… can help us, because we should be able to take some”— were seized on by critics who claimed Trump was suggesting violating international law by plundering another country’s resources and openly saying the U.S. was pursuing war for oil.