Without fear of Soviet intervention, Nazi Germany invaded Poland on September 1. Two days later Britain and France responded to the plight of their Polish ally by declaring war on Germany. Before September ended, however, German forces had crushed Polish resistance.
Like Czechoslovakia, Poland disappeared from the map of Europe. Soviet forces occupied eastern Poland on September 17. In October the Germans annexed Poland's western and northern districts to the Reich. Much of the country's central heartland--it included the cities of Lublin, Kraków, and the Polish capital Warsaw--became a German colony known as the Generalgouvernement.
In the autumn of 1939, Poland's total population numbered about 33 million. Ten percent--3.3 million--were Jews. Nazi Germany's Blitzkrieg military tactics and the partition of Poland brought two million Jews under German domination. For the Third Reich, this "Jewish problem" was one of unprecedented proportions. In some ways, however, the "Jewish problem" was more manageable in Poland than it had been in Germany, Austria, or the Protectorate of Bohemia and Moravia. According to Nazi racial ideology, Poles were much inferior to Germans. Eastern European Jewry--Polish Jews among them--ranked even lower. As part of what the Nazis called "subhumanity," Polish Jews should have no reason to expect even the modicum of respect that German Jews had received.
Still, the sheer number of Polish Jews--Warsaw alone was home to almost 400,000--created difficulties that the Germans had not faced before. What should be done with the Polish Jews? Acknowledging that "it is obvious that the tasks ahead cannot be laid down from here in full detail," Reinhard Heydrich's September 21 dispatch from Berlin was intended nonetheless to be an important part of the answer to that question.
While plans to ghettoize Polish Jewry were under way, other parts of the answer to the "Jewish question" were beginning to emerge, however dimly at the time, through Hitler's authorization of a so-called "euthanasia" program. The program targeted Germans who were physically or mentally disabled. During the winter of 1939-40, these "useless eaters" were being put to death at institutions in Germany and Austria that were equipped with gas chambers. Later, officials who worked for the euthanasia program would take their skills to such Nazi killing centers as Belzec, Sobibór, and Treblinka. There, Jews would be gassed by the tens of thousands.