This chapter puts forth the argument that democracies enjoy built-in advantages in long-run geopolitical competitions. It begins by defining key terms, such as “democracy” and “autocracy.” Then, drawing on the writing of political philosophers, such as Herodotus, Machiavelli, and Montesquieu, and contemporary social science research, this chapter explains the unique economic, diplomatic, and military advantages that democracies bring to the international arena. These advantages include: higher long-run rates of economic growth, access to international capital, larger and more reliable alliances, and a tendency to win international wars. It then explains how these advantages grant democracies an edge in amassing wealth and power, becoming great powers, and achieving global hegemony at rates greater than their autocratic rivals.