But ukrainians and Poles differentiated in language (as per what I've seen Ukrainians has a basis in the old Ruthenian language and has a lot of Polish loanwords)
Ok, I deviated -- the thing about Poland's Kresy is that it was the last of the great multi-national areas with Poles, non-Polonized Jews, Ruthenians (Belarussians, Ukrainians, Boyks, Łemkos, Hutsuls), Armenians, Germans and with Catholics, Orthodox, Mennonites and also Jewish secularists, orthodox, Hassids, Karaites, Litvaks and also Muslim Tartars
So, while it was "Poland", it was really part of the grand Piłsudski idea to re-create the Polish-Lithuanian commonwealth (a multi-national state)
If the Ukrainians and BElarussians and Lithuanians had agreed to this and the Polish Dmowski party not beeen so "Poland for the poles", then this united entity would have been able to stand up to Germany and Russia far better
instead the Lithuanians were pretty anti-polish, as were, even more so, the Ukrainians
These two seemed to see Polishness as a soft threat to their cultures (which it was) instead of seeing that there were the Nazis and Soviets who would slaughter their bodies...
On this I agree totally, if only Pilsudski survived to 1939. One of the curious things I noticed.....Hitler actually attended Pilsudski's funeral...and one of the first things he did when he invaded in 1939, was to post an honor guard at Pilsudski's grave. Perhaps he saw in Pilsudski a like-minded hater of Russians and Bolshevism, but I hardly could imagine Pilsudski liking Hitler all that much.
Wow. Big similarity between the ethnic disunity you describe in pre-WW2 Poland, and Ukraine today.