American Expeditionary Forces. Caption: "Last into war were the Americans who did everything with style and panache. They were young and brave and tough, if sentimentally attached to their pets." At the outbreak of the war, the United States pursued a policy of non-intervention, avoiding conflict while trying to broker a peace. After the sinking of seven U.S. merchant ships by submarines, Wilson called for war on Germany, which the Congress declared on April 6, 1917. The United States was never formally a member of the Allies but became a self-styled "Associated Power". The United States had a small army, but, after the passage of the Selective Service Act, it drafted 2.8 million men, and, by summer 1918, was sending 10,000 fresh soldiers to France every day.