Former U.S. ambassador to Saudi Arabia, Chas Freeman, said of Saudi Arabia, “One of the major things the Saudis have historically done, in part out of friendship with the United States, is to insist that oil continues to be priced in dollars. Therefore, the US Treasury can print money and buy oil, which is an advantage no other country has. With the emergence of other currencies and with strains in the relationship, I wonder whether there will not again be, as there have been in the past, people in Saudi Arabia who raise the question of why they should be so kind to the United States.” wikipedia