The United States entered World War I on April 6, 1917, when it declared war on Germany. The declaration came after a series of provocative acts from the German military and diplomatic corps. U.S. troops arrived in Europe by June 1917 but were largely ill-prepared for the kind of fighting taking place on the western front.  Preparation for the Saint-Mihiel Battle For months, American soldiers were used to augment French and British forces in Europe. As training improved and the number of...