America Enters World War One in 1917

America Enters the War in 1917
Fasttrack to America's Past

1917: A secret German message to Mexico

The Zimmerman telegram was a secret message sent by a German official named Arthur Zimmerman to Mexico in January 1917. It asked Mexico to:

enter the war on the side of Germany and
attack the United States.

The telegram, shown below, was sent in a secret code using numbers to stand for words. The German embassy (office) in Mexico City had a code book to convert the message back to the original words.

What Germany promised Mexico

    In the telegram, Germany promised Mexico that it would help Mexico conquer and take the land of Texas, Arizona, and New Mexico.

   Those states were part of the area that Mexico lost to the U.S. in the mid-1800s.

   Mexico refused to be part of Germany's plan, however. Mexican leaders knew full well they did not have the military strength to fight against the U.S.

The British intercepted the message, and broke the secret German code

    The British government intercepted the Zimmerman telegram when it was sent. After they deciphered it, they informed American officials of its contents.

   The decoded and translated message was given to President Woodrow Wilson. He released the contents of the message to American newspapers.

   The U.S. was still neutral as 1917 began. Anger over the telegram, however, led more and more Americans to favor entering the war.

   (In the telegram, shown on the right, "the "President" refers to the president of Mexico.)

America enters the war

   In February of 1917, Germany started using its U-boats for "unrestricted" submarine warfare in the waters around Great Britain. Some American ships and some belonging to other neutral nations were attacked and sunk.

   Anger over the Zimmerman telegram, and the new attacks by German submarines, convinced President Wilson that it was time to take a stand.

   In April of 1917, President Wilson went to Congress to ask for a declaration of war. Congress gave its approval. America entered the war on the side of the Allied Powers.

Click here to see in this newspaper
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The famous picture below shows President Wilson making his speech
to Congress asking for a declaration of war.

Looking deeper: A political cartoon

The political cartoon below was published in an American newspaper not long after the Zimmerman telegram was made public. The symbol of Germany is on the gloved hand holding the knife. Americans at that time also knew that Germany hoped to get Japan to join with Germany as well.

Zimmerman telegram images courtesy the National Archives.
The color photo print, political cartoon, and newspaper images
are from the Library of Congress.
The maps are by David Burns.
Some images have been resized for this page.