military service. The Commission on Training Camp Activities sought to improve the morals and morale of the troops. By the summer of 1918, about 2 million U.S. soldiers had arrived in France, about half of whom eventually saw front-line service; by the Armistice of November 11 approximately 10,000 U.S. soldiers were arriving in France daily. In 1917, Congress gave U.S. citizenship to Puerto Ricans when they were drafted to participate in World War I, as part of the Jones Act. In the end, the German Empire miscalculated the United States' influence on the outcome of the conflict, believing it would be many more months before U.S. troops would arrive and overestimating the effectiveness of U-boats in slowing the American buildup. Beginning with the Battle of Saint-Mihiel, the first major battle involving the American Expeditionary Forces, the leaders of the United States war efforts were General of the Armies John J. Pershing, Navy Admiral William Sims, and Chief of Air Service Mason Patrick. The United States Navy sent a battleship group to Scapa Flow to join with the British Grand Fleet, destroyers to Queenstown, Ireland and submarines to help guard convoys. Several regiments of Marines were also dispatched to France. The British and French wanted U.S. units to be used to reinforce their troops already on the battle lines and not to waste scarce shipping on bringing over supplies. The U.S. rejected the first proposition and accepted the second. General John J. Pershing, American Expeditionary Forces (AEF) commander, refused to break up U.S. units to serve as mere reinforcements for British Empire and French units. As an exception, he did allow African-American combat regiments to fight in French divisions. The Harlem Hellfighters fought as part of the French 16th Division, earning a unit Croix de Guerre for their actions at Château-Thierry, Belleau Wood, and Séchault. Women in the military American women never served in combat roles (as did some Russians), but many were eager to serve as nurses and support personnel in uniform. During the course of the war, 21,498 U.S. Army nurses (American military nurses were all women then) served in military hospitals in the United States and overseas. Many of these women were positioned near to battlefields, and they tended to over a million soldiers who had been wounded or were unwell. 272 U.S. Army nurses died of disease (mainly tuberculosis, influenza, and pneumonia). Eighteen African-American Army nurses, including