United States Timeline 1942-1953 By hsquinn Jul 20, 1942 First Atomic Bomb Apr 13, 1943 Jefferson Memorial 1945 Harry S. Truman is elected president Apr 1, 1945 Battle of Okinawa Apr 12, 1945 Death of President Roosevelt Aug 6, 1946 Hiroshima and Nagasaki Mar 12, 1947 Truman Doctrine 1949 Harry S. Truman is reelected as president Apr 4, 1949 NATO 1953 Dwight D. Eisenhower is elected president