Syria is hardly a state anymore: Turkey occupies part of it, the Kurds control a big chunk and are allied with the US, the Islamofascists control smaller parts. The US pumps oil to fund support for the Kurds fighting ISIS. If I were to guess, the Kurds control the oil and the US simply prevents the Syrian regime from regaining control.
Get back to me when the US loots everything from hundreds of thousands of tons of grain to washing machines, TV sets and toilets.