In the lead-up to the war, German operatives launched a series of sabotage operations in German territory in the guise that these were committed by Poles, in order to give Germany a pretext to invade Poland. These actions, implemented under Operation Himmler, targeted railway stations, customs houses, communication lines, etc. As part of Operation Himmler, on the night of August 31, 1939, German saboteurs wearing Polish uniforms seized the Gleiwitz radio station in Silesia, Germany, and aired a short anti-German message in Polish. This and other supposed Polish provocations were used by Hitler to launch what he called a “defensive war” against Poland, stating that “the series of border violations, which are unbearable to a great power, prove that the Poles no longer are willing to respect the German frontier.”
(Taken from Invasion of Poland – Wars of the 20th Century – World War II in Europe: Vol. 6)
BackgroundAt the end of World War I, the Allies reconstituted Poland as a sovereign nation, incorporating into the new state portions of the eastern German territories of Pomerania and Silesia, which contained majority Polish populations. In the 1920s, the German Weimar Republic sought to restore to Germany all its lost territories, but was restrained by certain stipulations of the Treaty of Versailles, which had been imposed on Germany after World War I. Polish Pomerania was known worldwide as the “Polish Corridor”, as it allowed Poland access to international waters through the Baltic Sea. The German city of Danzig in East Prussia, as well as nearby areas, also was detached from Germany, and renamed the “Free City of Danzig”, administered by the League of Nations, but whose port, customs, and public infrastructures were controlled by Poland.
In 1933, Hitler came to power and implemented Germany’s massive rearmament program, and later began to pursue his irredentist ambitions in earnest. Previously in January 1934, Nazi Germany and Poland had signed a ten-year non-aggression pact, where the German government recognized the territorial integrity of the Polish state, which included the German regions that had been ceded to Poland. But by the late 1930s, the now militarily powerful Germany was actively pushing to redefine the German-Polish border.
In October 1938, Germany proposed to Poland renewing their non-aggression treaty, but subject to two conditions: that Danzig be restored to Germany and that Germany be allowed to build road and railway lines through the Polish Corridor to connect Germany proper and East Prussia. Poland refused, and in April 1939, Hitler abolished the non-aggression pact. To Poland, Hitler was using the same aggressive tactics that he had used against Czechoslovakia, and that if it yielded to the German demands on Danzig and the Polish Corridor, ultimately the rest of Poland would be swallowed up by Germany.
Meanwhile, Britain and France, which had pursued appeasement toward Hitler, had become wary after the German occupation of the rest of Czechoslovakia, which had a non-ethnic German majority population, which was in contrast to what Hitler had said that he only wanted returned those German-populated territories. Britain and France were now determined to resist Germany diplomatically and resolve the crisis through firm negotiations. On March 31, 1939, Britain and France announced that they would “guarantee Polish independence” in case of foreign aggression. Since 1921, as per the Franco-Polish Military Alliance, France had pledged military assistance to Poland if that latter was attacked.
In fact, Hitler’s intentions on Poland was not only the return of lost German territories, but the elimination of the Polish state and annexation of Poland as part of Lebensraum (“living space”), German expansion into Eastern Europe and Russia. Lebensraum called for the eradication of the native populations in these conquered areas. For Poland specifically, on August 22, 1939 in the lead-up to the German invasion, Hitler had said that “the object of the war is … to kill without pity or mercy all men, women, and children of Polish descent or language. Only in this way can we obtain the living space we need.” In April 1939, Hitler instructed the German military High Command to begin preparations for an invasion of Poland, to be launched later in the summer. By May 1939, the German military had drawn up the invasion plan.
In May 1939, Britain and France held high-level talks with the Soviet Union regarding forming a tripartite military alliance against Germany, especially in light of the possible German invasion of Poland. These talks stalled, because Poland refused to allow Soviet forces into its territory in case Germany attacked. Unbeknown to Britain and France, the Soviet Union and Germany were also conducting (secret) separate talks regarding bilateral political, military, and economic concerns, which on August 23, 1939, led to the signing of a non-aggression treaty. This treaty, which was broadcast to the world and widely known as the Molotov Ribbentrop Pact (named after Soviet Foreign Minister Vyacheslav Molotov and German Foreign Minister Joachim von Ribbentrop), brought a radical shift to the European power balance, as Germany was now free to invade Poland without fear of Soviet reprisal. The pact also included a secret protocol where Poland, Finland, Estonia, Latvia, Lithuania, and Romania were divided into German and Soviet spheres of influence.
One day earlier, August 22, with the non-aggression treaty virtually assured, Hitler set the invasion date of Poland for August 26, 1939. On August 25, Hitler told the British ambassador that Britain must agree to the German demands on Poland, as the non-aggression pact freed Germany from facing a two-front war with major powers. But on that same day, Britain and Poland signed a mutual defense pact, which contained a secret clause where the British promised military assistance if Poland was attacked by Germany. This agreement, as well as British overtures that Britain and Poland were willing to restart the stalled talks with Germany, forced Hitler to abort the invasion set for the next day.
The Wehrmacht (German Armed Forces) stood down, except for some units that did not receive the new stop order and crossed into Poland, skirmishing with the Poles. These German units soon withdrew back across the border, but the Polish High Command, informed through intelligence reports of massive German build-up at the border, was unaware that the border skirmishes were part of an aborted German invasion.
German negotiations with Britain and France continued, but they failed to make progress. Poland had refused to negotiate on the basis of ceding territory, and its determination was strengthened by the military guarantees of the Western Powers, particularly in that if the Germans invaded, the British and French would attack from the west, and Germany would be confronted with a two-front war.
On August 29, 1939, Germany sent Poland a set of proposals for negotiations, which included two points: that Danzig be returned to Germany and that a plebiscite be held in the Polish Corridor to determine whether the territory should remain with Poland or be returned to Germany. In the latter, Poles who were born or had settled in the Corridor since 1919 could not vote, while Germans born there but not living there could vote. Germany demanded that negotiations were subject to a Polish official with signing powers arriving by the following day, August 30.
Britain deemed that the German proposal was an ultimatum to Poland, and tried but failed to convince the Polish government to negotiate. On August 30, the German Foreign Minister Ribbentrop presented the British ambassador with a 16-point proposal for negotiations, but refused the latter’s request that a copy be sent to the Polish government, as no Polish representative had arrived by the set date. The next day, August 31, the Polish Ambassador Jozef Lipski conferred with Ribbentrop, but as Lipski had no signing powers, the talks did not proceed. Later that day, Hitler announced that the German-Polish talks had ended because of Poland’s refusal to negotiate. He then ordered the German High Command to proceed with the invasion of Poland for the next day, September 1, 1939.