There were several causes for American involvement in World War One.The United States' policy in 1914 embraced issues concerning strict isolationism and neutrality.Although the United States hoped they would sustain their neutrality, they also thought it was essential for the U.S. to trade with disadvantaged Allies. Furthermore, the causes of United State's involvement into World War One extended due to factors such as, banking interests with the allies, German authoritarianism, Wilsonian idealism, unrestricted submarine warfare, and the Zimmerman Telegram. The contributions of all these dilemmas eventually lead to the United States entering the First World War on April 2nd, 1917.
After taking into consideration all the causes for the United States' participation into World War One, I believe the most persuasive act that motivated the U.S. to move into the war would be the Zimmerman Telegram, simply because it was their last straw.The other factors greatly impacted the U.S., however the Zimmerman Telegram was bound to create enough friction for the United States to finally act upon what they had originally hoped to steer clear of.
The unrestricted submarine warfare created conflict when the Germans issued the U-boat policy, which meant that they would not warn enemy vessels for their forthcoming explosions and as a result, they would fire at any ship whether it was an enemy merchant ship or allied vessels disguised as neutral ships, they were to enter at their own risk. It was inevitable, for the Americans had to fight back, especially after the sinking of the Lusitania on May 7th, 1915, given that it did kill 128 Americans and a year later with the sinking of the French channel streamer the Sussex. This infuriated the Americans, and on February 24th 1917, everything turned from bad to worse.
"Walter Hines Page, United States ambassador to Great Britain, transmits to th…