World War I: American Involvement, Then Post-War Disengagement

Though World War I started in August 1914, the United States—pursuing a policy of isolationism and diplomacy—did not officially enter the war until nearly three years later. When a German submarine sank the Lusitania in 1915, killing over 100 Americans, President Woodrow Wilson demanded an end to attacks on passenger ships. Germany complied until Jan. 31, 1917, when its resumption of unrestricted submarine warfare marked a turning point for U.S. involvement in the war. After seven U.S. vessels were sunk, President Wilson on April 2, 1917, asked Congress to declare war—which it did four days later.

Article continues after newspaper image from Nov. 11, 1918, issue of Wyoming State Tribune-Cheyenne State Leader

The government rapidly mobilized military resources, industry, labor, and agriculture. In the summer of 1918, fresh American troops under the command of General John J. Pershing played a decisive role in stopping a last-ditch German offensive. That fall, Americans were key participants in the Meuse-Argonne offensive, which cracked Germany’s vaunted Hindenburg Line. By October 1918, on the eve of Allied victory, a U.S. army of over 1,750,000 troops had been deployed in France.

President Wilson contributed greatly to ending the war. In a speech to Congress on January 8 he had outlined his Fourteen Points, defining the goals that America hoped to achieve by fighting the war and laying the foundation for a peaceful world after the war ended. One of his points called for the establishment of an association of nations to afford “mutual guarantees of political independence and territorial integrity to great and small states alike.”

In October 1918 the German government, facing certain defeat, appealed to Wilson to negotiate the war’s conclusion on the basis of the Fourteen Points. After a month of secret negotiations that gave Germany no firm guarantees, an armistice (technically a truce, but actually a surrender) was concluded on Nov. 11, 1918.

It was Wilson’s hope that the final treaties would be fair to all parties, but the passion and sacrifice of the war caused the European Allies to make severe demands upon their defeated foes, especially the Treaty of Versailles that Germany was forced to sign. Wilson compromised on the issues of self-determination, open diplomacy and other specifics, in an attempt to forge a lasting peace through the international organization he envisioned: the League of Nations. In the end, there was little left of Wilson’s original proposals except for the League of Nations itself.

Wilson had failed to involve Republicans in the treaty negotiations, and he returned to the U.S. with a treaty that stalled in a Senate committee. Wilson started a national tour to appeal for support. On Sept. 25, 1919, he suffered a crippling stroke. Critically ill for weeks, he never fully recovered.

In two separate votes—November 1919 and March 1920—the Senate rejected the Treaty of Versailles, and the U.S. did not join the League of Nations. This rejection set the tone for American foreign relations for the next two decades. America retreated back into isolationism, focusing on internal matters and the foreign affairs of only its immediate neighbors.

For more information, visit the A Guide to World War I Materials website provided by the Library of Congress.

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