The Treaty of Versailles had cut the German province of East Prussia off from the rest of Germany by a stretch of land known as the Polish Corridor. At the end of this corridor, on the Baltic coast, was the former German port of Danzig, now declared a ‘free city’. Germany demanded the return of Danzig and the construction of road and rail links through the Polish Corridor. The Polish government refused. The British and French governments, realizing Poland’s vulnerability, offered Poland the guarantee that, if attacked, they would come to her aid. But in reality, neither Britain nor France had the military means to honour such a guarantee.
In May 1939, Hitler and Mussolini strengthened their ties by signing the ‘Pact of Steel’, a ten-year alliance. Chamberlain, despite being an ardent opponent of communism, saw the need to bring the Soviet Union into Britain’s orbit if his guarantee to Poland could be realistically upheld. But negotiations between the two nations failed – much to the delight of Hitler.
Between May and September 1939, the Soviet Union, engaged in a conflict in the east with Japan, had no desire to be pulled into a war against Germany on her western front. Germany too wanted to avoid a war against the Soviet Union, being equally keen to avoid a war on two fronts. Hitler knew too that, despite the Pact of Steel, Italy was militarily weak and not ready for war.
Joseph Stalin realized that Hitler’s ultimate territorial ambition was to invade the east. Hitler had never made a secret of this. But with the Soviet Union’s military severely under-strength, expediency overrode ideology and on 23 August 1939, Germany and the Soviet Union amazed the world by signing a non-aggression pact. The pact committed the two nations to ten years of peace, together with a number of trade agreements and, as a secret clause, the agreement to carve up various territories between them, including an east–west division of Poland. Hitler was delighted with the result and, on hearing the news, slapped his knee in characteristic delight. Without the aid of the Soviet Union, Hitler could not envisage Britain or France being capable of upholding their guarantee to the Poles. The road to Poland was now free.