World War One and America's First Turn on the World Stage

When the guns of August opened in 1914 and Europe began tearing itself apart, most Americans wanted nothing to do with it. The war felt like exactly the kind of old-world dynastic quarrel that the founders had warned about and that three thousand miles of ocean had kept comfortably distant. Woodrow Wilson won reelection in 1916 on a platform that included the slogan He kept us out of war.

By April 1917 he was asking Congress for a declaration of war.

Several things changed his hand. German unrestricted submarine warfare, which began in earnest in February 1917, was sinking American merchant ships and killing American citizens. The Zimmermann Telegram, in which Germany proposed a military alliance with Mexico against the United States in exchange for help recovering Texas, New Mexico, and Arizona, produced outrage when its contents were published. The fall of the Tsar in Russia in March 1917 made it easier to frame the Allied cause as a fight for democracy rather than a coalition of empires.

America's entry was decisive not primarily because of what it delivered immediately but because of what it signaled to both sides. The German high command had gambled that unrestricted submarine warfare would starve Britain into submission before the Americans could mobilize in force. They were wrong. The United States raised an army of four million from a military establishment that had been tiny, shipped two million of them to France, and fed them into a front that had been grinding in stalemate for three years. By the summer of 1918, the German military situation had become untenable.

Wilson arrived at the Paris Peace Conference in January 1919 as a figure of almost messianic stature in much of Europe. His Fourteen Points, announced in January 1918, had offered a vision of the postwar order built on self-determination, open diplomacy, freedom of the seas, and a League of Nations that would arbitrate future disputes. The crowds that greeted him in Paris, London, and Rome were enormous.

The treaty he brought home was a compromise that satisfied nobody fully and disappointed many profoundly. The League of Nations, Wilson's most important achievement, was rejected by the US Senate, which refused to ratify the treaty. Wilson, in failing health after a stroke suffered during a national speaking tour to build support for the treaty, could not secure the two-thirds majority he needed. America retreated into a sullen semi-isolationism.

The war had demonstrated that America had the industrial capacity, the manpower, and the logistics to be a decisive military factor anywhere in the world. It had also demonstrated the limits of American willingness to translate that capacity into permanent international engagement. The gap between capability and commitment would be a persistent feature of American foreign policy for the next two decades.