Well, Germany was considered our enemy because of their submarines/U-boats were sinking American vessels. Germany also encouraged Mexico to attack the Americans through notes called the Zimmerman notes. Hopefully this helps.
The U.S were fighting in WW1 along with their allies all because of German submarine warfare. the release of cables attributed to the Germans encouraging Mexico to attack the U.S also the success of AntiGerman propaganda.
Germany influenced the United States' decision to enter World War I primarily through its unrestricted submarine warfare, which threatened American ships. Additionally, the Zimmermann Telegram, proposing an alliance with Mexico against the U.S., heightened tensions and rallied public support for war. Consequently, on April 2, 1917, President Wilson asked Congress to declare war on Germany.
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