Are democracies more likely to win the wars they fight? This question has been of interest to historians and philosophers since Thucydides. During the Enlightenment, the question was highly relevant to the great issues of the day, as thinkers such as Thomas Paine wondered how emerging republics like the United States and France would fare in war against monarchies. It reemerged in the twentieth century, when some worried whether the Western democracies had the stuff to stand up to Nazi Germany and its fascist allies. After World War II, Westerners fretted that an American Athens would ultimately fall short against a Soviet Sparta.