Before American Entered World War I
January of 1917.
Almost the entire world was caught in the midst of the Great War and up to then, the United States had managed to remain relatively neutral. Neutrality, however, was not very well defined. The U.S. may not have declared war on Germany or sent troops to Europe, but America was sending armaments to Great Britain and assured the Germans that any attacks on U.S. ships would amount to war. Anti-german sentiment was rising in America. German popped this bubble by trying to create a secret plan with Mexico. The German Foreign Secretary, Arthur Zimmerman, sent a secret telegram to the German embassy in Mexico, telling the German ambassador there to offer Mexico money, support, and a promise to return New Mexico, Arizona, and Texas if Mexico were to declare on the United States. Fortunately for the United States (and for Mexico), the Mexican government had no interest in taking on the United States army (they had just lost to the same army about 30 years prior).
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Going back to the action… You see the U.S. was already angry at the Germans. Their U-Boats had been wreaking havoc on seafaring vessels. At one point, the Germans had practiced unrestricted warfare— essentially meaning they’d attack anything they felt might be involved in carrying supplies for the war. America had already seen the sinking of the Lusitania, which killed 128 Americans, so America finally had to step in and tell the Germans to quit torpedoing everything that moved. However, the Germans realized that if they wanted to win the war, they were going to have to disrupt shipping channels with their submarines.
Arthur Zimmermann Sends a Telegram
So in comes German Foreign Secretary Arthur Zimmermann. He wanted to reinitiate unrestricted submarine warfare, but he knew that the United States would certainly join the war in Europe if he did. So, Zimmermann had a plan. He would start torpedoing ships again in February 1917. In the meantime, he needed a way to slow the arrival of American troops to Europe. He believed that if he convinced Mexico to declare war on the United States, then the US would be too slow to get to Europe and would need too many troops and supplies to stay home and fight the Mexicans.
Zimmermann launched his plan, writing a coded message for his ambassador in Mexico. Oddly enough, Great Britain had cut off German access to telegram lines to the U.S. Therefore, Zimmermann actually had to walk over to the U.S. embassy to send this telegraph (which is why he needed it coded). The U.S. typically refused to send coded messages for the Germans, but this time Zimmermann was able to convince the U.S. ambassador that it was of utmost importance and had to be sent.
Fortunately (but unbeknownst to the U.S.) Great Britain was reading all of the telegrams that were being sent to America from Europe. Long story short, almost all the telegram lines were routed through Great Britain so that they could get the electrical boost they needed to travel underneath the Atlantic ocean and reach the United States. So, Great Britain flagged the telegram from Zimmermann, passed it on to codebreakers, and promptly informed the United States that Germany was up to no good.
America Enters World War I
The best part? Many in the United States loudly protested the letter, saying it was a British hoax to try and convince the United States to join the war. Arthur Zimmermann himself quickly put a stop to these beliefs. He gave a speech explaining why he sent the telegram to Mexico, basically telling the United States, “Hey, part of my later said Mexico should only declare war on you if you decided to declare war on Germany. As long as you don’t do that, you’ll be fine.” Woodrow Wilson and the United States promptly declared war on Germany only a short few days after this speech.
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America and her allies would go on to defeat the Germans in World War I and no, Mexico didn’t declare war on the United States. They remained neutral throughout the war. However, German advisors did continue to appear in Mexico up through 1918. Zimmermann didn’t stop at Mexico, either. He and his German cronies also tried to incite wars and rebellions in Ireland and India, so that Great Britain would be bogged down during the war as well. Not long after the Zimmermann telegraph, Arthur Zimmerman resigned as German Foreign Secretary. The resignation was directly linked to the Zimmermann telegraph fiasco.
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