FAS expands and secures access to foreign markets for U.S. agricultural products by removing trade barriers and imposing U.S. tariffs under existing trade agreements. FAS works with foreign governments, international organizations, and the Office of the U.S. Trade Representative to establish international norms and rules to improve the accountability and predictability of agricultural trade. On December 1, 1938, the Department of the Foreign Agricultural Service was upgraded, placed directly under the authority of the Secretary and simply renamed the Foreign Agricultural Service. However, on July 1, 1939, President Franklin D. Roosevelt ordered the transfer of all diplomatic personnel, including agricultural attachés and commissioners, to the Foreign Department.