Late at night on August 23, 1939, the foreign ministers of the Soviet Union and the German Reich signed a “non-aggression treaty” that has come to be known as the Hitler Stalin Pact. The pact committed the two nations to a policy of friendship and mutual aid, provided for increased trade, and included secret protocols which laid the groundwork for the Second World War.
In 1989 the Swiss anarchist magazine, Banal, published the secret protocals in German. The addendum to the agreement provided for the division of Poland after the two countries would invade it from opposite directions. The invasion of Poland led to the war, as Britain and France, allied with Poland, declared war on Germany.
As a result of the German/Russian agreement, Communist Parties throughout the world defended Germany’s aggressive moves against France and Britain; the Comintern became an accessory to the Anti-Komintern alliance of Germany & Italy.
Critics of international Communism at the time recorded a song about the new party line: (h/t to Jack Ross for posting this on youtube) https://www.youtube.com/watch?v=Jl1r7E3e-ks
Under the terms of the pact, the Soviet Union acted to annex Estonia, Latvia and Lithuania. At the end of the war, Germany and Japan, as belligerents, were forced to give up territory, including some land that each country held even before the start of the war. But the USSR continued to control Estonia, Latvia and Lithuania until 1991.
Russia no longer is under control of the Communist Party, but Russian libertarians now point to the Putin regime as holding the characteristics of a fascist state: http://libertarian-party.ru/blog/an-appeal-to-western-libertarians-about-the-war-in-Ukraine
It is sad to see how much the legacy of authoritarianism and imperialism continues to dominate the Russian body politic.