FDR
The united states of America
President T. roosevelt
United States
United states
During World War, conservation of food and supplies was needed to feed Europe and the Army. The conservation leader during this time was the head of the United States Food Administration. The head of the agency was Herbert Hoover.
Joseph Stalin was the leader of the Soviet Union after World War II. While allies of Britain and the United States during the war, this was mainly because all considered Hitler to be their enemy. Directly, after the war, Britain and the United States ended their relationship with Stalin.
United States Navy operations during World War I happened in 1917.
The United States (USA), due to its "superpower" status (both economically and militarily) and international presence, is considered the leader of the free world. It can also be argued there is not just one leader - but the United States and the United Kingdom are possibly two of the leaders.
There was no one "world leader", but the two main competing nations were the United States and the Soviet Union.
Mao Zedong
No. Hitler was the leader of Germany during WW2. Franklin Delano Roosevelt was President of the United States.