The cause of the United States entering World War 1 in 1917 was because Germany sank their ship the Lusitania.
Answer:
First World War Causes
World War I began after the assassination of Austrian archduke Franz Ferdinand by South Slav nationalist Gavrilo Princip on June 28, 1914. Read more about Franz Ferdinand. Read more about why the Balkans became the “powder keg of Europe.”
Explanation:
