When war broke out in Europe in August of 1914, it seemed, to observers in the United States, the height of madness. The Old World and its empires were tearing each other apart, and while most Americans blamed the Germans, pitied the Belgians, and felt kinship with the Allies, they wanted no part in the carnage. Two years into war President Woodrow Wilson won re-election by pledging to keep out of the conflict. Yet by the spring of 1917-by which point millions had been killed for little apparent gain or purpose-the fervor to head "Over There" swept the country. America wanted in.
The...

Signed on June 28, 1919 between Germany and the principal Allied powers, the Treaty of Versailles formally ended World War I. Problematic from the very beginning, even its contemporaries saw the treaty as a mediocre compromise, creating a precarious order in Europe and abroad and destined to fall short of ensuring lasting peace. At the time, observers read the treaty through competing lenses: a desire for peace after five years of disastrous war, demands for vengeance against Germany, the uncertain future of colonialism, and, most alarmingly, the emerging threat of Bolshevism. A century after...