[EliRivers]

As I recall from conversation, it's that the USSR did not jointly invade Poland with Germany; this is evidenced in the fact that they did not invade on the same day. Furthermore, the USSR wasn't even invading Poland; the USSR was striking West through Poland in order to protect Poland from Germany.

[Footpost]

Aha, of course, just like the Berlin Wall was an "Anti-Fascist Protection Barrier"!

https://en.wikipedia.org/wiki/Berlin_Wall

[gus_massa]

Just in case your comment is taken out of context, I'd recommend starting it with:

In schools it was taught that …