In autumn 1939, the Soviet Union, pursuing its strategic military and defensive goals, started the process incorporating Latvia, Lithuania and Estonia. Their accession to the USSR was implemented on a contractual basis, with the consent of the elected authorities. This was in line with international and state law of that time.
The blame for the tragedy that Poland then suffered lies entirely with the Polish leadership, which had impeded the formation of a military alliance between Britain, France and the Soviet Union and relied on the help from its Western partners, throwing its own people under the steamroller of Hitler’s machine of destruction.
This message is part of the Kremlin’s policy of historical revisionism and an attempt to erode the disastrous historical role of the Molotov-Ribbentrop Pact and to reject the historical fact of the Soviet attack at Poland in September 1939.
On August 23, 1939, Nazi Germany and the USSR signed the Molotov-Ribbentrop Pact with the Secret Supplementary Protocol, which divided Poland and other Eastern European countries between these two totalitarian powers.
On September 1, 1939, Nazi Germany attacked Poland and the Soviet Union attack at Poland started on September 17 – in this way, Nazi Germany and the USSR started the implementation of the Secret Supplementary Protocol to the Molotov-Ribbentrop Pact.
In other words, it was the Molotov-Ribbentrop Pact that put Poland “under the steamroller of Hitler's machine of destruction” during WWII.
Read similar examples of the Russian historical revisionism concerning this issue - Signing of the Molotov-Ribbentrop pact thwarted the UK’s expansionist plans in Europe, The Molotov-Ribbentrop pact did not violate the rights of the Polish state, The shift of all blame for WWII outbreak at the Ribbentrop-Molotov pact the best example of manipulation of history.