The Nazi–Soviet Non-Aggression Pact: Negotiation and Implementation

In summer 1939, as the danger of war in Europe increased, Germany and the Soviet Union accelerated diplomatic contacts despite their ideological hostility. Germany wanted to avoid Soviet intervention when it attacked Poland; the arrangement subsequently reached also enabled the Soviet Union to expand its control in Eastern Europe. German foreign minister Joachim von Ribbentrop and Soviet People’s Commissar for Foreign Affairs Vyacheslav Molotov negotiated and signed the treaty. Naming only the two countries’ leaders obscures the actual negotiators.

A telegram sent on August 19 by Germany’s ambassador to the Soviet Union, Friedrich-Werner von der Schulenburg, relayed the Soviet draft non-aggression treaty. The draft originally provided for a five-year term and specified that a special protocol concerning foreign-policy interests should be signed at the same time. The final text extended the term to ten years, while supplementary arrangements continued to be drawn up alongside the main text. This diplomatic exchange shows that the public pledge of non-aggression and the secret division of interests were linked from the negotiating stage.

References: [1]

The formal treaty was signed in Moscow, and its text bears the date August 23, 1939. The parties pledged not to use violence, aggression, or attacks against each other, either individually or jointly with other states. If one party became the target of military action by a third country, the other was not to support that country. They also agreed to maintain consultations, avoid joining groups of states directed directly or indirectly against the other party, and resolve disputes through exchanges of views or arbitration commissions.

The term clause provided for ten years of validity, with an automatic five-year extension unless notice of termination was given one year before expiry. The closing provisions also required prompt ratification and an exchange of instruments of ratification in Berlin, while explicitly stating that the treaty entered into force immediately upon signature. Signing, entry into force, and completion of ratification procedures were therefore separate stages: the exchange of ratification instruments was not the date on which the treaty first became effective. The public clauses governed relations between the two states but offered no guarantee of third countries’ territorial security.

References: [1]

The secret additional protocol of the same date addressed the boundaries of the parties’ interests in the event of territorial and political changes in Eastern Europe. In the Baltic region, Lithuania’s northern boundary was designated as the dividing line between their spheres of influence, while Lithuania’s interest in the Vilnius region was recognized. In Poland, the proposed line broadly followed the Narew, Vistula, and San rivers. Whether an independent Polish state would be retained, and with what boundaries, was left to further political developments and subsequent arrangement between the two powers.

The protocol also recorded Soviet interest in Bessarabia and Germany’s declaration of political disinterest in that region, and required strict secrecy. These provisions were not territorial settlements agreed to by Poland, the Baltic states, or Romania, nor were they completed changes to international borders. Initially, they constituted a secret arrangement between Germany and the Soviet Union; only later were they translated into occupation through force and additional agreements.

References: [1]

In a telegram of August 31, US ambassador to the Soviet Union Laurence Steinhardt reported that the Supreme Soviet had ratified the treaty that evening. Speaking at the session, Molotov presented it as a peace arrangement and blamed Britain, France, and Poland. This was the Soviet government’s political justification at the time, rather than a neutral conclusion about the causes of war. Another American diplomatic telegram relayed a TASS report that Germany and the Soviet Union had exchanged instruments of ratification in Berlin on September 24.

War had already begun before the ratification procedures were completed. Germany invaded Poland on September 1; Britain and France declared war on Germany on September 3; and the Soviet Union invaded Poland from the east on September 17. The non-aggression treaty reduced German concerns that Soviet intervention might obstruct its operations, while the secret arrangements provided a diplomatic framework for the two countries to partition Poland. Written commitments to peace between the parties thus coexisted with military expansion against a third country.

References: [2] [3] [1]

On September 28, 1939, Germany and the Soviet Union signed a further Boundary and Friendship Treaty in Moscow, establishing a dividing line through occupied Polish territory. An accompanying secret protocol revised the August arrangements: most of Lithuania passed into the Soviet sphere of influence, while the Lublin region and part of the Warsaw region entered the German sphere. The actual occupation line did not precisely match the initial secret protocol’s proposals, so an account of implementation must also consider the subsequent agreements.

The language of these documents reveals how the two powers excluded Poland itself from deciding its political fate. Implementation did not consist of a border clause automatically taking effect. It resulted from a combination of military occupation, bilateral negotiation, and redrawing of lines. The public documents and secret annexes must be read separately to avoid treating later revisions as if everything had already been settled on August 23.

References: [1]

The Soviet Union subsequently attacked Finland and, in 1940, occupied and annexed the three Baltic states, Bessarabia, and other territories, with profound consequences for local populations. Germany did not intend to honor its ten-year pledge of peace. On June 22, 1941, German forces launched a full-scale invasion of the Soviet Union; the treaty had lasted less than two years in practice.

The significance of the Nazi–Soviet Non-Aggression Pact lay not simply in a temporary suspension of conflict between hostile regimes. Its public provisions and secret divisions together changed Eastern Europe’s security environment. It did not establish a sustainable peace order, but instead created conditions for aggression, occupation, and territorial reorganization. Germany’s eventual attack on the Soviet Union exposed the enormous gap between the written term of the agreement and political and military action.

References: [1]