/ What proportion of the Polish population collaborated with the Nazis?
Very few Poles collaborated, the Nazis did not allow it, it was usually only on a local level for hunting Jews and often it was coerced under the threat of violence.
That is not to say that some Poles who hated the Jews were not willing accomplices but only on this subject.
Ethnic Germans are something different as they saw the invading Nazis as conquering heroes.
It is wrong to castigate Silesians as Kaczynski has done, the ethnic Germans were forcibly removed from Poland after 1945, very few remained in Western Poland.
Hitler planned for Poznan to be the capital of the Eastern kingdom, the city was to be run by the local German population as the admin centre
for all the Slavic speaking peoples.
The city was being rebuilt to suit this purpose, with areas of the city set aside for the German elite, such as Solacz down the road from me.
The Zamek in Poznan was being redesigned to be identical to his palace in Berlin.
The goal was to not only eliminate the Jews and other ethnic groups, it was to remove the educated classes in Slavic countries.
The Easterm empire was to be the labour force for the Third Reich but the overall aim was to greatly reduce this population making it easier to control.
The reproductive experiments were also aimed at breeding the slaves to be obedient and docile with heavily controlled reproductive programs.
The anti-semitic movement which inspired Hitler began in Austria at the turn of the century, Vienna elected an antisemitic mayor, Karl Lueger.
He was opposed by the Emperor Franz Joseph I, who had granted Jews equal rights.
Many of the leading Nazis, the main architects of the Holocaust were in fact Austrian Catholics who had been influenced by Karl Lueger and his followers.
It is wrong to say Hitler expected the Catholics to be predisposed to help, he had long abandoned the Catholic religion, in favour of his new pagan religion.
It would be also wrong to say that the Catholic church was vehemently opposed to the Nazis persecution of the Jews, it often did nothing to assist non-Catholics.
It did not officially collaborate but it also did not encourage it's flock to help the Jews, it took a neutral stance which in my opinion is a form of collaboration.
Publicly it would denounce the rounds-ups etc., however in my opinion this was more for show.
The Vatican did not want to be seen as helping Jews, despite the fact it could have done much to save Jews, it did little.
That is not to say that some priests did not sacrifice themselves to help Jews, many did but they did it out of morale conscience and not as official church policy.
This is in contrast to many of the Lutheran and Protestant churches which setup escape networks to help the Jews.
Hitler at no stage desired Poland as a partner, his initial plan was to free the ethnic Germans, this was completely incompatible with working with Poland as a partner.
His plans for Poznan and Poland in general were drawn up long before the invasion.
The Jews were to be eliminated the Polish population reduced to manageable numbers.