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Jan Rydel

The Causes and Circumstances of the Outbreak of the Second World War

07 January 2020
  • Ribbentrop and Molotov pact
  • Stalin
  • Second World War
  • Hitler
  • Molotov-Ribbentrop Pact
  • Soviet Union

The order set by the Treaty of Versailles that shaped interwar Europe and sanctioned the appearance of myriad independent states in East-Central Europe had a number of weaknesses, the key one being the absence of two large continental powers Germany and Russia while it was being decided. As regards the former, the public in the countries of the Entente affected by population losses and destruction as well as exhausted by a war of several years was so much reluctant towards Germany that it was plain impossible to treat it as a partner during the Paris peace conference. At the time of the event, Russia was experiencing a hard-thought civil war between Bolsheviks and representatives of the ancien regime, whose resolution was nowhere to be seen, and as a result – despite attempts at mediation – it proved futile to determine which party to the conflict should represent the country. Given the terms of peace dictated to Germany and isolation to surround victorious Soviet Russia, both powers rejected the Versailles system and sought its revision. That general attitude brought them closer and in 1922 they concluded an accord in Rapallo that formed the basis for their friendly political relations, intensive economic and military cooperation in the area of technology and the arms industry, as well as training.

In 1925, Germany signed treaties in Locarno with France, Belgium, Great Britain and Italy that guaranteed its western border as laid down in the Treaty of Versailles. However, it refused to sign a similar treaty with Poland and Czechoslovakia, which caused much concern in those countries, both because of the unambiguous though indirect threat issued by Germany and the stance taken by France, which by accepting that and not some other arrangement put into question its own loyalty towards Poland and Czechoslovakia. After Locarno, thanks to support of France and Great Britain, Germany joined the League of Nations and even received the status of a permanent member of its Council, the equivalent of today’s UN Security Council. That meant that Germany’s isolation was over and the country had become a member of the international community in its own right. Symbolic of those changes was the Nobel Peace Prize received by the German Foreign Minister Gustav Stresemann. As the new German policy caused concern in Moscow as regards future cooperation, the partnership between Germany and the Soviet Union was reinforced by a friendship accord concluded in Berlin in 1926 and extended in 1931.

At the turn of the 1920s and the 1930s, the Soviet Union took steps in order to ensure the country’s full participation in international relations and was an active and constructive participant in negotiations on the international Kellog-Briand Pact assuming renunciation of war as a tool of international policy (Treaty for Renunciation of War). Before that pact entered into force in February 1929, the ‘Litvinov Protocol’ was signed in Moscow where the USSR and its western neighbours, including Poland, decided that the provisions of the Kellog-Briand Pact would come into force even before its formal ratification. The Protocol paved the way towards intensification of Polish-Soviet relations, which resulted in the signing of a non-aggression pact between Poland and the USSR on 25 July 1932. It was a highly precise document which foresaw that the parties to it were also to treat as aggression: any act of violence that affects the integrity and inviolability of the territory or political independence of the other Contracting Party, even if such actions are not accompanied by a declaration of war and its all possible manifestations.

At the time of the Polish-Soviet rapprochement, Europe was experiencing growing tensions related to the successes of Adolf Hitler’s party heading for power in the German Reich. It was particularly strong in Polish-German relations, which is why Polish diplomats discreetly probed the French ally on several occasions, trying to establish how strong France’s response would be in the case of an armed conflict with Germany. The last such probe took place after Germany’s leaving the League of Nations on 14 October 1933. As all the attempts rendered negative results, the value of the alliance with France seen from the Polish perspective was significantly reduced. In the circumstances, the Polish envoy in Berlin Józef Lipski asked Adolf Hitler whether Germany took into consideration compensating Poland for its decreased sense of security as the former had left the League of Nations. That opened the way for the signing, on 26 January 1933 after intensive and secret negotiations, of a Declaration between Poland and Germany on non-application of violence. The European public was much surprised by the document since the Polish-German antagonism was considered insurmountable. Consequently, it was suspected that apart from the publicly known text of the declaration some secret convent was made under which Poland was joining the German side, which was not true, and – what is more – the declaration did contain a statement that its signing did not have any impact whatsoever on the legality of previous treaties and commitments made by the parties to it. To appease the Soviets, who also had concerns as to the true meaning of the Polish-German declaration, Poland concluded an agreement with them already in 1934 concerning the extension of the non-aggression pact until as late as 1945.

At that time, Polish politicians became convinced that the alliance with France – given its passive and submissive stance – might not continue to be the only pillar of the Polish security policy. Also, Poland had never harboured any illusions as to the ability of the League of Nations to ensure peace in Europe. Similarly sceptical was Poland’s attitude to the French-promoted attempts to set up a collective security system in East-Central Europe with an instrumental participation of the USSR, their obvious and direct result being ceding hegemony in this part of the continent to the Soviets. For that reason Marshal Józef Piłsudski, Poland’s de facto political leader, championed the notion that Warsaw needed to keep an even distance between Berlin and Moscow, as exemplified by somewhat symmetrical agreements concluded in 1932 and 1934, respectively. Soon to pass away, Piłsudski was at the same time issuing the warning that such a balance around Poland would not last for more than four years.

Thanks to the signing of the declaration, the relations between Poland and Germany improved very soon. Germany ended a customs war with Poland dating back to the time of the Weimar Republic and both sides adopted a milder attitude as regards their respective national minorities as well as softened virulent press propaganda. Some contacts were also established in the field of culture and high-level visits became relatively frequent. The initiative concerning closer ties came mostly from Germany, hoping to win Poland as an ally against the USSR. Yet it was a wrong calculation. Germany did not recognise the border with Poland, which for the latter was a sine qua non condition for any possible further rapprochement. No open or secret Polish-German political or military alliance took place. Poland – despite incentives – did not join the Anti-Comintern Pact, a loose grouping of countries allied with the Third Reich. Poland did not plan making any territorial gains in cooperation with Germany. The circle of Piłsudski’s supporters in power in Poland (known as the Sanation) did not support national socialism, and there were hardly any supporters of that movement among members of the opposition. Last but not least, there were also no cooperation between Poland and Germany as regards discrimination of Jews.

At first, the course of events in Europe confirmed that Piłsudski’s predictions were correct. In March 1935, Germany announced that it would not respect the arms restrictions imposed by the Treaty of Versailles. That step did not meet with any de facto response from France while Great Britain concluded a naval pact with Germany that sanctioned a considerable extension of the German navy. A year later, on 7 March 1936, German troops entered the Rhineland in a blatant violation of the Treaties of Versailles and Locarno. In the circumstances, Poland ensured France yet again of its readiness to meet its obligations stemming from their alliance in case of a conflict with Germany. However, neither France nor any of western countries, or the League of Nations, did anything more than issue purely verbal protests. Still, after long negotiations, on 6 September 1936 France granted Poland a large loan for modernisation of its armed forces, a proof that, although weakened, the Polish-French Alliance continued to be in force.

In May 1935, France and the USSR as well as Czechoslovakia and the USSR entered into bilateral agreements on mutual assistance in case of a German invasion. The Soviet-Czechoslovak accord was to become operational only under the condition that France offer military support to Czechoslovakia first (casus foederis). Looking good on paper, the agreements in question were de facto dead politically, inter alia because no serious attempt was made to agree with Poland how the Soviet Union sharing no border with Germany or Czechoslovakia was supposed to render military assistance to its new partners.

Poland’s political standing began to change radically when in 1938 Germany triggered the implementation of its expansive agenda and annexed Austria (12–13 March 1938), took control of Klaipeda at the expense of Lithuania (23 March 1938) and, in particular, partitioned Czechoslovakia. During a conference in Munich (29–30 September 1938), Czechoslovakia, although the most loyal ally of France, was pressed by its allies and agreed to cede to Germany a vast borderland known as the Sudetenland important in economic and strategic terms. Although no party to the conflict or participant of the Munich conference, Poland nevertheless forced crisis-ridden Czechoslovakia to cede Zaolzie (lands beyond the Olza River) to it. The contentious area populated mostly by Poles had been stealthily attacked and seized by Czechoslovak troops in 1920 when the Bolshevik army was poised for attack near Warsaw. Even if the taking control of Zaolzie by Polish troops on 2 October 1938 was much justified and the entire operation did not result from any arrangements with Germany, the impression it made in Europe was that Poland collaborated with Hitler.

On 24 October 1938, the Polish envoy in Berlin Józef Lipski received a list of demands from the German Foreign Minister Joachim von Ribbentrop intended as the basis for a new general arrangement of mutual relations between both countries. The German demands included the incorporation of the Free City of Gdańsk to the German Reich, the construction of an extraterritorial motorway and a railway link between East Prussia and the rest of the Reich, Poland’s joining the Anti-Comintern Pact as well as permanent political consultations between Poland and Germany. The objective behind the demands, extraordinarily moderate according to the Germans, was to force Poland to decide whether it supported Germany or not. Polish diplomats were greatly surprised by the German demands. For its part, Germany was astonished by Poland’s veiled and then unambiguous refusal to accept them as its conclusion was that such a step would turn the country into a German fiefdom while the Polish Government treated Poland’s territorial integrity and sovereignty as inalienable. When interned in Romania in 1940, the Polish Foreign Minister Józef Beck did not mince words about the consequences of Poland’s hypothetical agreement: We would have conquered Russia together with Germany and then we would have been grazing cows for Hitler in the Ural.1 The resolution of that stage of the Polish-German dispute came as a result of the German seizure of territorially reduced Czechoslovakia on 15 March 1939, with the Protectorate of Bohemia and Moravia established in Czechia and Slovakia becoming an independent state ‘under the care of the German Reich’. That move meant a violation of the relatively fresh Munich agreement as well as a crude exposure of the British and French appeasement policy, which both powers could not stomach any more. Responding, Great Britain decided to give Poland assurances on 31 March 1939, the basis for the British-Polish alliance. Conditioning its own policy towards Germany on Great Britain at that time, France also renewed its alliance with Poland. In response, on 28 April Adolf Hitler renounced the non-aggression pact with Poland as well as the naval accord with Great Britain. On 5 May 1939, Józef Beck delivered his great speech at the Sejm rejecting the German demands. It was clear that Poland and Germany were on a collision course now.

The events in Europe were closely followed by Joseph Stalin and Soviet diplomats. They were aware of their comfortable position as they could choose which side of the escalating conflict to support and which one would assure them more benefits. Since April, talks had been going on in Moscow with representatives of Great Britain and France yet no progress was being made as both countries treated them mainly as a kind of demonstration targeting Germany. In actual fact, Stalin had already decided to change the paradigm of the Soviet foreign policy, i.e. initiate cooperation with Hitler. The obstacle was the Commissar of Foreign Affairs Maxim Litvinov, a son and brother of rabbis from Białystok born as Meir Wallach, distinguishing himself as a staunch enemy of Nazism and a passionate champion of bringing the USSR closer to western democracies. Already on 15 April 1939 during a sitting of the Politburo of the Bolshevik Party, Stalin rejected Litvinov arguments for an alliance with Great Britain and France. On 3 May 1939, Litvinov was formally dismissed and a purge took place among Soviet diplomats of Jewish origin. Litvinov was now replaced by Stalin’s blind follower, the cynical chair of the Council of People’s Commissars (equivalent of a Prime Minister) Vyacheslav Molotov. Talks went full steam ahead in the last days of July 1939. First, an extensive economic agreement was negotiated, providing for, inter alia, large supplies of Soviet raw materials to Germany. Following that success, the parties agreed to enter into political talks. Joachim von Ribbentrop flew to Moscow, and in the night from 23 to 24 August he negotiated a non-aggression pact with the Soviet partners. A more important and sensational part of the agreement was laid down in a secret protocol. It provided for a division of East-Central Europe between Germany and the Soviet Union, the sphere of influence of the latter including Finland, Estonia, Latvia and Bessarabia in Romania. As regards Poland, the Soviet Union additionally committed to invade it and occupy its eastern part up to the line marked by the rivers Narew, Vistula and San.

Thanks to the conscious action of an opposition-minded diplomat from the German embassy in Moscow, the content of the secret protocol was transmitted without delay to US, Italian and French diplomats. The British also had incomplete knowledge about it and it was they that passed on a veiled warning to the Polish ambassador Edward Raczyński who sent it to Warsaw. Unfortunately, Polish authorities at that time had an entirely false image of the Soviets and their politics. Polish intelligence in the USSR ‘got blind’ as a result of the ‘great purges’ of 1937–1938, and minister Beck was most probably surrounded by Soviet agents of influence. As a result, he was not aware of the Kremlin’s changed course towards Germany and he also thought that after Stalin’s great purges the Soviet Union and the Red Army were seriously weakened and de facto unable to launch any large-scale operations. Consequently, he failed to grasp how precarious Poland’s position had become. His optimism was reinforced by the signing of a military alliance with Great Britain on 25 August 1939.

Germany attacked Poland on 1 September 1939. On 3 September, Great Britain and France declared war on Germany, which meant that one objective of the Polish foreign policy had been reached, that of not reducing the Polish-German war to a local conflict. Now, in compliance with the military agreements in force, the fighting Poles expected the allies to launch full-scale military operations within 15–16 days. Unfortunately, the allied commands concluded already on 4 September that they would not be able to effectively help Poland and that they would limit themselves to military demonstrations against Germany, focusing on preparations for future military action. That decision was finally confirmed by a conference of French and British Prime Ministers accompanied by highest-ranking commanders taking place in Abbeville on 12 September 1939. Those arrangements were not transmitted to Poland as that could have broken its spirit of resistance. It is known now, however, that the arrangements made in Abbeville were known to Soviet intelligence in no time at all. In that way, the Soviets were assured that the campaign mounted by Poland was doomed and they could safely hit the country from the east. In the morning of 17 September 1939, the Polish ambassador in Moscow Wacław Grzybowski was summoned to appear at the Foreign Affairs Commissariat where a note was read out to him saying that as the Polish state had ceased to exist, the non-aggression pact was not valid anymore and the Soviet army was entering Polish territory in order to protect the population of Western Ukraine and Western Belarus. The Soviet note was based on a blatant lie as at the time of the Soviet invasion still around a half of Poland’s territory, including important administrative centres, was not occupied by the Germans and the Polish Government and chief command were present in Poland preparing the defence of the south-eastern part of the country (known as the Romanian Bridgehead). Despite Soviet assurances that the USSR was not involved in a war with Poland, bloody fights were taking place along the entire border, in some locations lasting until the first days of October 1939. The ‘Polesie’ Operational Group led by Gen. Franciszek Kleeberg fighting with Germans and Soviets capitulated on 6 October 1939. The German-Soviet brotherhood in arms was symbolically sealed by a joint victory parade in Brest-Litovsk received by Generals Heinz Guderian and Semyon Krivoshein. It took place as early as 22 September 1939.

The Molotov-Ribbentrop Pact, also known as the Stalin-Hitler Pact, paved the way for the latter’s attack on Poland, as it gave him certainty that no real help from the outside would reach Polish territory in the decisive weeks of the campaign. Further, the pact guaranteed Hitler that, not threatened from the east, he would be able to de facto conquer or control the entire continental Europe, install his occupation regimes throughout it and execute the ‘final solution to the Jewish question’. Managed from Moscow, the Comintern ordered communist parties across the world to stop anti-fascist propaganda and change entirely the course towards Germany, now together with the Soviet Union making a ‘camp of global peace’. The Polish state authorities – both when still in the country and later when in accordance with the Polish constitution they began to operate in exile, still enjoying full international recognition – on numerous occasions confirmed a state of war with the Soviet Union. However, they did not make a formal proclamation of a state of war with that state as its allies France and Great Britain remained neutral towards the USSR. Finland’s case was different as on 30 November 1939 it – a part of the Soviet sphere of influence specified in the Molotov-Ribbentrop Pact – was attacked by the USSR and duly protested at the League of Nations, which after considering the complaint on 14 December 1939 stripped the USSR of its membership as an aggressor and called on its member states to aid Finland. In summary, it can be concluded that despite preliminary losses and obstacles, Germany and the Soviet Union in the interwar period became respected members of the international community in their own right yet as totalitarian regimes they betrayed that status by unleashing the most dreadful of wars inflicted on the human race to date.

JAN RYDEL is a historian and his research areas are Central and Eastern Europe and Polish-German relations in the 19th and 20th centuries. He is the author of ‘Politics of History in Federal Republic of Germany. Legacy – Ideas – Practice’ (2011) and ‘Polish Occupation of North Western Germany. 1945–1948. An Unknown Chapter in Polish- German Relations’ (2000, German edition 2003). Until 2010 he was a researcher and a professor at Jagiellonian University and is currently a professor at the Pedagogical University of Cracow.


1. Cited after Marek Kornat, ‘Idee i podstawy polityki zagranicznej II Rzeczypospolitej’, in: Marek Kornat, Wojciech Materski, Między pokojem a wojną. Szkice o dyplomacji polskiej, Warsaw 2015, p. 30