Distinguishing between those focused on territorial or ethnic disputes and those dedicated to a global messianic mission is critical in the next war. During the battle against communism, we initially treated the entire communist world as monolithic, a mistake we cannot repeat with the Islamic world. We must learn the differences between Sunni and Shi'ite, Ghilzai and Pushtun, moderate and radical. Our overzealous search for enemies from within in the 1950s and its tragic consequences must be remembered and not repeated.