Politics cannot be separated from the means to exercise it, and energy, short of armed power, is perhaps one of the most effective means in the service of international politics. Although other forms of energy such as hydropower and other renewable resources as well as nuclear power come to play a central role from time to time in the relations of two or more countries, it is oil and increasingly natural gas which is really the supremely political energy source having the power to profoundly affect international relations. Because most oil moves internationally, because its trade is of enormous monetary value, because huge profits are to be made, because it is a vital necessity for most importing countries, because it is of crucial importance to the economies of the oil exporting countries and the balance of payments of developing countries for all these reasons, the ordinary day-to-day flows of international trade in oil are in effect the result of enormous and conflicting pressures among governments, companies and international organizations. It is not an exaggeration to say that oil is the most important single commodity to shape world history in the past hundred years.