If we want energy security, then we have to reduce our appetite for fossil fuels. There's no other way. Other issues may crowd the headlines, but this is our fundamental challenge. Big challenges require bold action and leadership. To get the United States off fossil fuels in this uneasy national climate of terrorism and conflict in the Persian Gulf, we must treat the issue with the urgence and persistance it deserves. The measure of our success will be the condition on which we leave the world for the next generation.