| •1933 | United States extends diplomatic recognition to the Soviet Union |
| Adolf Hitler becomes chancellor of Germany |
| •1935–1937 | Neutrality Acts |
| •1939 | Germany occupies Czechoslovakia |
| Germany and Soviet Union invade Poland; World War II begins |
| •1940 | Battle of Britain begins |
| Tripartite Pact signed |
| •1941 | Lend-Lease Act |
| Fair Employment Practice Committee created |
| Atlantic Charter signed |
| Germany invades Soviet Union |
| •December 7, 1941 | Pearl Harbor bombed |
| •December 11, 1941 | Germany and Italy declare war on the United States |
| •1942 | Congress of Racial Equality established |
| Manhattan Project approved |
| Roosevelt orders internment of Japanese Americans |
| •1943 | Zoot suit riots |
| •June 6, 1944 | D Day invasion begins |
| •1945 | Final U.S. offensive against Japan, with victories at Iwo Jima and Okinawa |
| •February 1945 | Yalta Conference |
| •May 1945 | Germany surrenders |
| •August 1945 | U.S. drops atomic bombs on Hiroshima and Nagasaki |
| •September 1945 | Japan surrenders |