This book is a counterpoint to the prevailing view that the United States is an imperialist nation that has violently pursued power in the world to advance its own narrow interests. The basic theme is that at the dawn of the 20th century, there were six democracies in the world, but by century's end, democracy was ascendant. This epic historical transformation has been thanks in great measure to the vision and sacrifices made by Americans. Matthew C. Price examines the great conflicts of the 20th century, showing how American democratic principles have utterly reshaped global values and politics.

The defeat of fascism and imperialism in World War II led to the Marshall Plan, the single most influential rebuilding program in human history. The fostering of democracy in Japan, the establishment of the UN, and the fall of the Soviet Union reshaped the world in unforeseen ways. America has dedicated itself to democracy in the Middle East, to democratization in China, and to the larger quest for the spread of liberal democratic principles worldwide, even when the struggle is difficult, dangerous, and ongoing. Early in the century, Woodrow Wilson said that America should make the world safe for democracy. In taking up that challenge, the United States changed human history.