The Saudis are facing an unexpected new challenge to their primacy in the empire of oil. North America, which had once been their best customer, is quickly becoming their most potent competitor. Hydraulic fracturing, the controversial and ecologically dubious extraction process more commonly known as "fracking," has opened up vast new reserves of oil in Alberta, North Dakota and other areas. The production potential is so great that the United States, rather than being an oil importer reliant on suppliers in the troubled regions of the Middle East, could soon be a major exporter. The energy independence for which a generation of politicians have clamored is at hand.