The document summarizes the key events leading up to and during World War I and the United States' involvement. It describes how the assassination of Archduke Franz Ferdinand led Austria-Hungary to declare war on Serbia, pulling in allies on both sides. While the US initially remained neutral, attacks on American ships by German U-boats and the discovery of a German plot with Mexico turned public opinion against Germany. President Wilson asked Congress to declare war in April 1917. Over 4 million American troops were deployed, known as the American Expeditionary Forces, who arrived on the Western Front in mid-1918 and helped secure an Allied victory before the war ended on November 11, 1918.