president of the Naval War College in Newport, Rhode Island in February 1917. Just before the U.S. entered the war, the Wilson administration sent him to London as the senior naval representative. After the U.S. entry in April 1917, Sims was given command over U.S. naval forces operating from Britain. He received a temporary promotion to vice admiral in May 1917. The major threat he faced was a highly effective German submarine campaign against freighters bringing vital food and munitions to the Allies. The combined Anglo-American naval war against U-boats in the western approaches to the British Isles in 1917–18 was a success due to ability of Sims to work smoothly with his British counterpart, Admiral Sir Lewis Bayly. Sims believed the Navy Department in Washington, which was effectively headed by Assistant Secretary Franklin D. Roosevelt, was failing to provide him with sufficient authority, information, autonomy, manpower, and naval forces. He ended the war as a vice admiral, in command of all U.S. naval forces operating in Europe. Shortly after the Armistice , Sims was promoted to temporary admiral in December 1918 but reverted to his permanent rank of rear admiral in April 1919 when he was assigned as president of the Naval War College. Attack on Daniels In 1919 after the war ended in Allied victory, Sims publicly attacked the deficiencies of American naval strategy, tactics, policy, and administration. He charged the failures had cost the Allies 2,500,000 tons of supplies, thereby prolonging the war by six months. He estimated the delay had raised the cost of the war to the Allies by $15 billion, and that it led to the unnecessary loss of 500,000 lives. Secretary of the Navy Josephus Daniels was more of a politician than a naval strategist, but he ably countered the accusations. He pointed to Sims' anglophilism, and said his vantage point in London was too narrow to assess accurately the overall war effort by the U.S. Navy. Daniels cited prewar naval preparations and strategy proposals made by other American leaders during the war to disprove Sims' charges. Despite the public acrimony, Sims emerged with his reputation unharmed, although some historians believe it cost him promotion to the rank of Admiral of the Navy. He did however serve a second tour as president of the Naval War College (1919–1922). It was during his time as the Naval War College that he wrote and published