My initial feeling around these kinds of things is always ‘Well, park an aircraft carrier there and force them to clean up their act.’ But then I realize that shit like that is exactly what led to the current problems in the first place.
Just tell the Saudis that while we might not approve of their war in Yemen, they can go get the oil and sell it at regular market price.
That said I am curious if anyone would buy the oil if someone went there with a tug boat and fetched the ship.
The problem with colonial forces installing democracy in 3rd world countries is that eventually they leave, and then all the old problems come back, AND the native liberal and progressive movements are completely compromised as traitors.
ISIS exists because of USA (and other countries - including my own) involvement in the middle east.
Britain was in India for 150 years and it was barely enough.