Roots of War: Wanting Power, Seeing Threat, Justifying ForceEver since Thucydides pondered reasons for the outbreak of the Peloponnesian War, writers, philosophers, and social scientists have tried to identify factors that promote conflict escalation: for example, history (tomorrow's wars are often rooted in yesterday's conflicts), changing balance of power among nations, or domestic political forces. In the end, however, these causes are constructed by human beings and involve the memories, emotions, and