German-Soviet Nonaggression Pact

German-Soviet Nonaggression Pact, also called Nazi-Soviet Pact, Hitler-Stalin Pact, or Molotov-Ribbentrop Pact; treaty between Germany and the Union of Soviet Socialist Republics (USSR), signed in Moscow on August 23, 1939—a few days before the beginning of World War II—by Nazi foreign minister Joachim von Ribbentrop and Soviet commissar for foreign affairs Vyacheslav Molotov, and in the presence of Soviet dictator Joseph Stalin. The nonaggression pact pledged neutrality in the event either party should become involved in a war. It also contained a secret protocol that divided Eastern and Central Europe into German and Soviet spheres of influence and provided for the division of Poland between the two powers.

Although Stalin and Nazi dictator Adolf Hitler were ideological adversaries, they found overriding reasons to bury their differences. Hitler needed an arrangement with Stalin in order to neutralize the USSR in his forthcoming invasion of Poland. Stalin wanted to extend Soviet frontiers westward for security reasons and to avoid involving the Soviet Union in a war for which it was not prepared. The open provisions of the pact came as a tremendous shock to the rest of Europe, not least because Stalin had been negotiating for an alliance with Britain and France to help defend the USSR in the event of a Nazi invasion.

Shortly after the pact was signed, the two powers invaded Poland. The partition of the country was completed on September 29, with the division between Germany and the Soviet Union established at the Bug River. In 1939 and 1940 the Soviet Union invaded the territories included in its sphere of influence, annexing the Baltic States (Lithuania, Latvia, and Estonia) and the region of Bessarabia (then a part of Romania) and extracting territorial concessions from Finland.

During the opening phases of World War II relations between the USSR and Nazi Germany became increasingly acrimonious. For Hitler, the nonaggression pact was only a temporary expedient that could be disregarded when necessary in his quest to expand Germany’s borders further eastward. At a secret Nazi conference on July 31, 1940, the decision was made in principle to invade the Soviet Union in the spring of 1941, ideally after having forced Britain to capitulate. German-Soviet relations became further strained by the presence of German troops in Finland and Romania and a disastrous visit to Berlin by Molotov in November 1940. Preparations for Operation Barbarossa, the German code name for the invasion plan, proceeded swiftly, and the decision to attack the USSR was confirmed in a war directive of December 18, 1940. The pact ceased to function when Germany invaded the Soviet Union on June 22, 1941. Following the war, however, the Soviet Union’s expanded borders were formally recognized by the Western powers.