There are many different causes for conflict throughout history. For example, in World War II the Japanese were driven by their need for oil. Similar forces are at work in the world today, and the potential for conflict over resources is likely to increase. Oil and gas are the most vital resources and will generate the greatest competition for control. The United States, Japan, and Europe are dependent on Middle East oil. Due to oil, the U.S. must provide at least minimum military support to the Persian Gulf. It must also find ways to reduce its dependence on Persian Gulf oil. The president has said that the lack of an assured energy supply is the single greatest threat to our country and to our allies.