The Telegram That Plunged America Into World War

The telegram, as received by the German ambassador to Mexico.

(National Archives and Records Administration)

In the early hours of August 5, 1914, shortly after Britain declared war on Germany in response to Germany’s invasion of Belgium, a British ship named the Telconia slipped out to sea to strike the first blow against the kaiser. Although the Telconia was armed only with grappling hooks, not guns, that blow may well have been the one that, four long, blood-drenched years later, won the war.

The Telconia was a ship built to service underwater communications cables, and off the German coast at first dawn she fished up the German transatlantic cables and cut them. This forced Germany to carry on its communications with the world by wireless and by other means that the British could intercept.

Naturally Germany used elaborate codes to safeguard its diplomatic and naval messages and—typically German—the government was utterly confident that its codes were unbreakable. The British, however, have a national genius for code breaking and were, in fact, soon reading the German traffic with ever-increasing speed and accuracy.

By the end of 1916, both the Allies and the Central Powers were reeling. The war’s cost in men and money had been appalling, and both sides were rapidly reaching the limits of their resources. The Battle of the Somme, which began on July 1, 1916, and lasted for months, alone had cost a million casualties. Britain was spending $10 million a day on war materiel and had nearly exhausted its financial assets and ability to borrow.

President Woodrow Wilson was determined to negotiate a peace “without victory,” to force the combatants to sit down and reach a compromise. But so terrible had been the sacrifices that neither side was willing to consider a negotiated peace. Each demanded victory to justify its losses.

And each side increasingly realized that the colossus of the New World was the key to that victory. Britain and France, already heavily dependent on the United States as a source of food, munitions, and war loans, sought to bring the U.S. into the war on their side. The British, as talented at propaganda as they were at code breaking, had used the “rape of Belgium” and the sinking of the liner Lusitania—which had cost 115 American lives—to successfully paint Germany as the villain in the war in the minds of most Americans.

But while probably a considerable majority of Americans wished for Allied victory, far fewer were willing to go to war to achieve it. And a very large number of German immigrants—most American cities at this time had German-language daily newspapers—still supported their old country.

Germany, meanwhile, unable to tap America’s immense industrial and agricultural resources because of the Royal Navy’s blockade, needed to keep those resources from reaching the Allies. And it needed to keep the United States neutral. But those two needs were incompatible. Only unrestricted submarine warfare—sinking merchant ships in the war zone without warning and without picking up survivors—could stop the flow of American food and arms and force Britain to sue for peace. But nothing was more likely to bring the United States into the war than the sinking of unarmed American ships.

By the beginning of 1917, the German government had decided it had no choice but to order its navy to begin unrestricted submarine warfare, beginning February 1. As Field Marshall Paul von Hindenburg explained at a secret conference on January 9, 1917, “Things cannot be worse than they are now. The war must be brought to an end by whatever means as soon as possible.”

In hopes of weakening the United States should it enter the war, Germany decided to stir up trouble between the U.S. and Mexico. Mexico had been in the throes of revolution since 1911, and its relations with its northern neighbor could hardly have been worse. Twice President Wilson had intervened, first in 1914 at Veracruz and then in 1916 when he sent General John J. Pershing and 6,600 troops into Mexico to capture Pancho Villa, who had raided American territory and killed several people. (Villa led Pershing a merry chase around northern Mexico and never came close to being run to ground.)

On January 16, 1917, the German foreign secretary, Arthur Zimmermann, sent his ambassador in Mexico a cable instructing him to offer Mexico an alliance in the event of war between Germany and the United States. It promised Mexico in exchange a joint war effort, generous financial support, and help in recovering its “lost territories” in Texas, New Mexico, and Arizona.

The Zimmermann telegram, as it soon became known, was in British hands before it reached the German ambassador in Mexico, and as soon as it was decoded, the British government realized that here, at long last, was the means of moving American public opinion and, even more important, President Wilson, from neutral to belligerent. The only questions were when to put the message into American hands for maximum effect and how to protect the secret that the British had broken the German codes.

The Germans announced unrestricted submarine warfare on February 1, which caused Wilson to break diplomatic relations. But, deeply invested in finding a way to “peace without victory,” he still refused to go beyond that. Then on February 24 the British gave the text of the telegram to the American ambassador, who quickly forwarded it to the State Department. The acting secretary (the secretary, Robert Lansing, was away for the weekend) immediately took it to the White House. On February 28, the text was released to the Associated Press, and on Thursday, March 1, 90 years ago today, it was in banner headlines in every newspaper in the country. The public outrage, from one coast to the other, was palpable. Political support for neutrality drained away until even Woodrow Wilson—as stubborn a man as has ever occupied the White House—realized he had no choice.

A month later, the United States was at war with Germany, the Allies were saved, and America’s remoteness from world affairs came to an end. Never has a single telegram so changed the world.

(As this is a history website, it should be noted that Barbara Tuchman’s book The Zimmermann Telegram made her famous and launched her career as one of the country’s leading narrative historians, twice winner of the Pulitzer Prize. It remains the best book on the subject and a wonderful read nearly 50 years after it was first published.)

—John Steele Gordon writes “The Business of America” for American Heritage magazine. His most recent book is An Empire of Wealth: The Epic History of American Economic Power (HarperCollins).