September 1939: German Invasion of Poland

After months of provocations demanding the immediate transfer of Danzig to Germany and plebiscites on return to Germany held in the Polish Corridor, Germany invaded Poland on 1 September 1939. This invasion is the beginning of the Second World War in Europe.

Germany and Poland had longstanding territorial disagreements even since part of the new Polish Republic was formed from German territory. None of the Weimar Republic governments recognized Poland’s western border or the independence of Danzig and they complained about Poland’s mistreatment of the German minority there. Although Hitler suppressed anti-Polish rhetoric, the Nazis also considered Danzig to be an essential part of the German Reich and expected for it to be turned over. Control of Danzig and some kind of extraterritorial road or railway across the Corridor were both Nazi demands.

For most of his time in power, Hitler wanted to establish an alliance with Poland, because he believed that Poland was the country best situated to assist in an invasion of the USSR and because doing so would deprive France of its most important ally. To this end, Hitler did not intend to annex the Polish Corridor or invade Poland, but he did expect Poland to at least be willing to discuss the issue of Danzig. After Germany’s invasion of Memelland in March 1939, Poland became increasingly concerned about the prospect of German aggression to seize Danzig by force and sought an alliance with Britain. Hitler was enraged by this development, as it demonstrated a hostility on the part of a nation that he had tried to befriend. For Hitler, Poland’s alignment with Britain and unwillingness to discuss Danzig after March 1939 demonstrated that Poland would never become a German ally and that his plans needed to change.

If Poland would not become an ally, then Poland was an obstacle between Germany and the USSR and another way for France and Britain to threaten Germany. In order to achieve his primary goal of invading the USSR, Hitler first needed to defeat France, the greatest threat to its power. If Poland was a hostile nation rather than an ally, it would need to be defeated before Hitler could invade France. The fact that Poland did contain an oppressed German minority was an additional reason to invade.

Hitler’s belief that Poland could be made into an ally meant that Poland was the last country to be targeted by the Nazis prior to the Second World War. It is only Hitler’s realization of the deep hostility of the Polish leadership to any alliance with the Nazis, particularly one that would likely have resulted in the loss of Danzig through negotiation, that sparked the war. This conflict occurred with France’s most significant eastern European ally and just after the invasion of Czechia convinced Chamberlain that Germany could only be stopped by war, meaning that this conflict, unlike other instances of German aggression in central and eastern Europe, involved Britain and France, thus escalating it into a ‘world war’.