1921-1941 By Caleb Nelson Period: Mar 4, 1921 to Aug 2, 1923 Warrren G. Harding Presidency died in office due to natural causes Period: Aug 2, 1923 to Mar 4, 1929 Calvin Coolidge Period: Mar 4, 1929 to Mar 4, 1933 Herbert Hoover Presidency Period: Mar 4, 1933 to Apr 12, 1945 FDR Presidency died in office due to natural causes Dec 11, 1941 America Enters WW2 Aug 9, 1945 Fat Man is dropped on Nagasaki Sep 2, 1945 WW2 Ends