Well, even that would not prevent you from Hitler's attack. He wanted Danzig, all the German territories from pre 1914 at least. And in his book he wrote more things about Poland and what his future plans with that (lebensraum etc.) it would probably be better for Poland to stand fast with the Allies in 1938 (when Hitler demanded Czechoslovakia... then his military was still weak...). However the British and French morale / government vision / persons prevented this.
To get back on - topic, Russia is really needed and probably not opressive, plus releasing PL-LT would be nice...
Tim
I think that you are relying too much on HoI games instead of refering to better historical sources. Hitler wanted Danzig which wasn't part of Poland at that time. It was a "free city". He also wanted a highway trough Corridor, not entire western Poland. In his book he stated that his greatest enemy was France, not Poland. And yes, he wanted Lebensraum but he never said where it would be. If we go ahistorical, and Poland is Allied to Germany, I'm pretty sure that Lebensraum would start right after eastern polish border (which would start somewhere in Russia after succesful Barbarossa). Anyway we go here too much offtopic. I'm back on topic.