On May 18, 1917, the United States took a major step into the global conflict of World War I when the first units of the American Expeditionary Force (AEF), commanded by General John J. Pershing, were ordered to France. This moment marked the beginning of America’s direct military involvement in the war and signaled a turning point in both the conflict and the nation’s role on the world stage. Though the United States had declared war on Germany only weeks earlier, the deployment of American troops demonstrated the country’s commitment to supporting the Allied powers and shaping the outcome of the war.
At the start of World War I in 1914, the United States had attempted to remain neutral. Many Americans believed the war was a European conflict that should not involve the United States. However, tensions steadily increased as Germany intensified its unrestricted submarine warfare in the Atlantic Ocean. German U-boats attacked merchant and passenger ships, including vessels carrying American citizens and goods. Public opinion shifted further after the revelation of the Zimmermann Telegram in early 1917, in which Germany encouraged Mexico to join the war against the United States. These events ultimately convinced President Woodrow Wilson to ask Congress for a declaration of war against Germany on April 6, 1917.
General John J. Pershing was selected to command the American Expeditionary Force because of his experience, leadership abilities, and reputation as a disciplined military officer. Pershing believed American soldiers should fight as an independent force rather than simply replacing exhausted Allied troops. This approach helped maintain American identity and morale while allowing the United States to demonstrate its growing military power. Pershing’s leadership would later become one of the defining elements of America’s participation in the war.
The order sending the first AEF units to France represented more than a military deployment. It symbolized the arrival of a new industrial and military power into a war that had devastated Europe for nearly three years. Although the first American troops were relatively small in number compared to the massive armies already fighting, their presence boosted Allied morale. France and Great Britain, worn down by years of trench warfare and enormous casualties, welcomed the arrival of fresh American forces and resources.
Once in France, American troops began training and preparing for combat alongside Allied forces. Over time, the AEF grew into a massive army of more than two million soldiers. American troops played important roles in major battles such as Cantigny, Belleau Wood, Saint-Mihiel, and the Meuse-Argonne Offensive. Their contributions helped weaken German resistance and pushed the war toward its conclusion in November 1918.
The deployment of the American Expeditionary Force also had long-term consequences for the United States. The nation emerged from World War I with increased global influence and a stronger sense of international responsibility. America’s involvement in the conflict demonstrated its industrial strength, military capability, and growing importance in world affairs.
May 18, 1917, therefore stands as a significant date in history. The order sending General Pershing and the first American troops to France marked the beginning of a new chapter for the United States — one in which it would play a decisive role in shaping global events during the twentieth century.
Use This Figure in the Classroom
Discussion Questions
- Why did the United States initially try to stay out of World War I, and what changed public opinion by 1917?
- How did General John J. Pershing influence the role of American troops in World War I?
- Why do you think the arrival of American forces boosted Allied morale in Europe?
Classroom Activity
Mapping America’s Entry into World War I
Have students trace the journey of the American Expeditionary Force from the United States to France on a world map. Students should identify major ports, troop routes, and key battles involving American forces. Afterward, discuss the logistical challenges of transporting an army across the Atlantic during wartime.
Debate Prompt
Should the United States have entered World War I in 1917, or remained neutral?
Assign students to argue either for intervention or continued neutrality using historical evidence from the period.
Writing Assignment Idea
Letter from the Front
Ask students to write a fictional letter from the perspective of an American soldier arriving in France in 1917. Students should describe their emotions, expectations, and observations about joining the war overseas.
Printable Quote
“The arrival of American troops in France marked the moment the United States stepped onto the world stage as a global military power.”