Michael Howard is one of the great scholars of contemporary Western war history. His understanding of war is based on a summary of historical experience and analysis of existing war theories. He believes war is the product of rational factors, and that war stems from politicians’ fear of enemy states’ increased power, or annihilation or restriction of their own territory. The existence of states is a primary cause of war, but it is also a prerequisite of maintaining peace. Nationalism has, and continues to trigger war, and at the same time it is a tool for states to conduct war with. War is impossible to wipe out entirely, but must be controlled.