The United States has learned to depend heavily on petroleum and its associate, natural gas, for energy and for raw materials. This dependence is less flexible than has been postulated. In spite of grandiose federal discussions about the energy mixes, progress toward replacing oil with other things is limited. It doesn’t appear feasible to make dramatic changes in the United States consumption patterns before our natural oil is depleted. Currently, we need oil to survive. Of cause, oil can be purchased from foreign sources but the worlds oil supply is finite. In addition, natural petroleum has become a potent political weapon to which the United States is increasingly vulnerable, and we're depleting our domestic supply.