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The Mexican Expedition, 1916-1917

Campaigns of World War I

A century ago, the United States joined what was then called the "Great War." The conflict, and America's involvement that helped bring it to an end, cast a long shadow across the twentieth century. In addition to massive destruction and loss of life, it shattered the European power system and brought economic turmoil, revolutions, collapse of empires, the birth of new nationstates, and the rise of totalitarian movements.

The war's outbreak in August 1914 shocked the United States. At this time, the Army was a constabulary force, barely adequate to police America's new empire in the Caribbean and Pacific, although after the War with Spain in 1898, Secretary of War Elihu Root had led important reforms. The United States invested in coastal defenses and a fleet to guard its shores, but its Army was simply too small to make an impact on European battlefields and lacked modern equipment such as motorized vehicles, machine guns, rapid-firing artillery, airplanes, and tanks. Its largest standing formation was a regiment. Not until June 1916 did Congress authorize an expansion of the Army, dual state-federal status for the National Guard, and the creation of an Army Reserve.

Meanwhile, the United States faced threats closer to home. To the south, Mexico was in the throes of revolution. In March 1916, a cross-border raid on Columbus, New Mexico, caused President Woodrow Wilson to declare a partial mobilization for a "punitive expedition" and to defend the border.

In early 1917, the president decided that America had run out of diplomatic options. In April, he asked Congress to declare war against Germany. But the U.S. Army, numbering only 133,000 men, was far from ready. The president ordered nearly 400,000 National Guardsmen into federal service, while the War Department built thirty-two cantonments where new divisions could be mobilized and trained. On 5 June, 9.5 million men registered for America's first conscription since the Civil War. The Army created a new combined-arms formation—the square division—and then corps, field armies, and support units, as well as new branches such as the Air Service, the Tank Corps, and the 3.7 million men and trained 200,000 new officers to lead them.

In June 1917, the 1st Expeditionary Division deployed to France, arriving in time to parade through Paris on the Fourth of July. On that occasion, a spokesman for Maj. Gen. John J. Pershing declared at the tomb of the hero of the American Revolution, "Lafayette, we are here!" In September, the first National Guard division deployed, the 26th Division from New England. By war's end, the American Expeditionary Forces had grown to two million soldiers and more than forty divisions. Among them were over 200,000 African American soldiers who served in segregated units, including four infantry regiments that fought under French command.

During 1918, American "doughboys" learned to fight in battles of steadily increasing scale: Cantigny, the Marne, Aisne-Marne, St. Mihiel, and Meuse-Argonne, adding thirteen campaign streamers to the Army flag. The soldiers faced machine guns, tanks, and a frightening new weapon of mass destruction, poison gas. Overall, in little over six months of combat, the American Expeditionary Forces suffered more than 320,000 casualties, including 50,280 killed.

The war that had promised to "make the world safe for democracy" ended with an armistice on 11 November 1918, followed by a deeply flawed peace. Although the U.S. Senate refused to ratify the Treaty of Versailles, American soldiers served in the Occupation of the Rhineland until 1923, before withdrawing from Europe altogether. The war sowed the seeds of future conflict that within a generation led to a second and even greater world war.

The United States will never forget the American soldiers who fought and died in the First World War. America's first unknown soldier was laid to rest on 11 November 1921 in the Tomb of the unknowns in Arlington National Cemetery, where soldiers still stand guard. The United States created permanent American military cemeteries in France, Belgium, and Britain to bury the fallen. To this day, memorials to their sacrifice can be found across America. The last surviving U.S. Army veteran of the war did not die until 2011. It is to all the doughboys, those who returned and those who did not, that the U.S. Army Center of Military History dedicates these commemorative pamphlets.

Director, CMH Histories Division

About the Author

Julie Irene Prieto received her Ph.D. from Stanford University in 2013 and joined the U.S. Army Center of Military History in October 2014 as a Presidential Management Fellow. At the Center, she specializes in the history of the U.S. Army in Latin America. Her most recent article, "The Sword and the Book: The Benjamin Franklin Library and U.S.-Mexican Relations, 1936–1962," was published in the December 2013 issue of the journal Book History.

Sale to the Public

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Domestic Publication Date: 15 May 2016
GPO S/N: 008-029-00600-6 (Paper); CMH Pub 77–1
Pp. 72; illustrations, maps, further readings

The Punitive Expedition

The Punitive Expedition - Mexico       9 March 1916 - 5 February 1917