1942-1953 By Josh Allen 1942 President Roosevelt approves work on nuclear weapons 1944 Allies invade France 1945 Roosevelt begins his 4th presedency 1945 President Roosevelt dies and Truman becomes President 1945 Germany surrenders 1945 First successful nuclear weapon test 1945 2 nuclear weapons dropped on Japan leading to Japan's surrender 1946 Atomic Energy Act passes 1947 Atomic energy plants begin construction 1948 Soviet Union blockades Berlin 1949 Soviet successful nuclear weapon test 1950 US begins work on thermonuclear weapon 1950 Korean War begins 1950 McCarthyism begins 1950 Vietnam War begins 1951 22nd Amendment passed 1952 First successful hydrogen bomb detonation 1953 Eisenhower becomes President 1953 Korean Armistice