It’s not a gold backed currency any longer, hasn’t been in a long time. The USD, like all currencies is only valuable because the people believe it has value, so it’s not really that oil gives it value or gold or whatever else, it’s public perception. As I said though, what do you think will happen to the dollar if everyone in the world realizes that the American government doesn’t control mega billions of dollars worth of gold, so it becomes obvious that we couldn’t back the value of the dollar up with gold even if we wanted to? Public perception of the USD could change overnight.