"The Soviet defeat by Poland in 1920 left a deep enmity. This was to help lead, first, to the persecution of the Polish minority in the Soviet Union in the 1930s, notably with the murderous ‘Polish Operation’ of 1937–8, then to Soviet alliance with Nazi Germany in partitioning Poland out of existence in 1939, and to a marked hostility toward Polish nationalism as the Germans were driven back in 1944. In the case of Poland, the Soviet animus against the post-World War One settlement found particular focus."