Ok, after WW1, when Poland was rebuilt, they received some sections of land from defeated Germany (e.g. the province Posen, Poznan) and Russia.
The next problem was that the Polish interwar authoritarian military government had imperial ambitions as well, and tried to take land from the weakened neighbours Germany and the Soviet Union. Actually there was a little known war going on between Poland and Germany, with in this case Poland as the agressor, in the 1920s. Since Germany’s Reichswehr was restricted due to the Versailles treaty, the government used the first the Freikorps and later the SA as auxillary troops in the Baltic regions.
Since the SA gained this way a kind of official role, this obviously helped the Nazis to become respectable.
Then, to understand Hitler’s imperial ambitions, you’ll have to look back to the mid 19th century:
Germany only existed as a nation since 1871, but became a major player in Europe very soon. All other European major powers (Britain, France, Belgium, Netherlands etc.) had overseas colonies, from which quite a bit of their wealth came. In German government circles, it was considered that, to become an equal player, Germany would also have to aquire colonies (They called it “Ein Platz and der Sonne” politics). Unfortunately Germany came about 200 years late and the world was already pretty much divided among the older powers. Especially Kaiser Friedrich Wilhelm II, he of WW1, used his fledgling navy to put pressure on the existing powers, leading to several crisises at the end of the 19th century, early 20th century (Morocco Crisis, Kanonenbootpolitik). Eventually this drive to challenge the existing powers in Europe led to WW1.
There were other political theorists and philosophers (e.g. Dietrich Schäfer) during the late 19th century, who, instead of going overseas, preached an expansion of Germany eastwards into Russia and other lands “not properly used by the local inferior population”, the “Lebensraum Politik”.
Now Hitler grew up in the multicultural country of KuK Austria Hungary.
The Austrians didn’t take their colonies overseas, but right across their border. This way their country contasined people from a lot of backgrounds, Slavic, Hungarians, Jews (In this case I don’t mean the assimilated Jews of Germany, who, with the exception of their religion were indistinguishable from their Christian neighbours, but Jews from Galicia and other Eastern European places, who dressed distinctly (look at traditional orthodox Jews in Jerusalem to get an idea) and lived in enclosed rural communities for centuries, with their very own customs).
This Austrian-Hungarian empire was not a multicultural meltingpot, but had a distinct class system, based on ethnic origin, with people looking down on each other:
On top were the German speaking Catholic Austrians, followed by the Hungarians, the Muslims (Bosnia) then came the Slavs followed by the Jews.
This is the enviroment Hitler grew up in.
This also explains why Hitler’s movement attracted a lot of supporters in rural Catholic Southern Germany, with a culture quite similar to Austrai, while he had serious problems in cosmopolitan protestant places like Berlin or Hamburg.
Hitlerstill believed that a powerfull country needed colonies and an enslaved population there to do the menial tasks, but he followed the route given by the 19th century chauvinists, preaching eastwards expansion.
Polish interwar agression against Germany made it believable for many Germans to follow his ideology, and I doubt that without the Polish attempts to increase their territory in the 1920s by attacking German territory, many Germans would have believed Hitler’s decoy of sept 1, 1939 at Gleiwitz. There were continued border tensions between the two countries. Hitler just usded them to his own ends, and there is a quote from him stating that in every negotiation between governments, there should be a few disputes left open, so that one has an excuse to attack the other country.
Jan