Douglas left the post at the end of 1939 and returned to the United States. There he accepted the presidency of Mutual of New York Life Insurance Company, a financially remunerative position that allowed Douglas to continue his involvement in public issues. An internationalist, Douglas was an early member of the Committee to Defend America by Aiding the Allies, and lobbied Roosevelt to provide more aid to Great Britain. Nonetheless, Douglas campaigned for Wendell Willkie in the 1940 presidential election, largely because of Roosevelt's violation of the "two-term" tradition. With America's entry into the Second World War, Douglas sought to return to public service. After a short period as deputy to Averell Harriman, the American Lend-Lease representative in Britain, Douglas was named deputy administrator of the War Shipping Administration (WSA). Douglas's appointment came in response to the growing criticism of the WSA's chief administrator, Admiral Emory S. Land, who nonetheless kept his post due to his friendship with the president. As deputy administrator, Douglas emerged as the effective head of the agency, addressing the difficult task of managing the country's shipping needs while fighting a global war. He served as deputy administrator until medical issues and growing tensions with Land led to his resignation in March 1944, after which he traveled to Europe to serve as a special adviser to General Lucius D. Clay on the reconstruction of German finance after the war. Rockefeller Foundation Beginning in 1935, Douglas would serve as a member of the Rockefeller Foundation where he maintained a position on the executive committee from 1936–1939. From 1942–1947, Douglas served as a trustee before being appointed as the United States Ambassador to the United Kingdom in 1947. Ambassador to the Court of St. James's In February 1947, Douglas was appointed as the ambassador to the United Kingdom, after the untimely death of the previous appointee, O. Max Gardner. As ambassador, Douglas enjoyed an enhanced status, as the new Secretary of State, George Marshall, delegated considerable authority to his subordinates. Because of this, he played an important role in the passage and implementation of the Marshall Plan as it related to the United Kingdom, and was closely involved in coordinating the American and British response to the Berlin Blockade in 1948. In April 1949 he suffered an accident while fly fishing that permanently damaged his left eye and restricted his involvement in official matters while he underwent a