Some years after NATO, Stalin made his alliance real. On May 14 1955, Albania, Bulgaria, Czechoslovakia, the German Democratic Republic, Hungary, Poland, Romania, and the Soviet Union signed the Warsaw Pact. This defensive military treaty stated that the signatories would come to the aid of any member nation that fell victim to an attack by an aggressor nation. The Warsaw Pact was a way for the Soviet Union to maintain very strict control over its satellites, which led to many deaths, and eventually, one of the causes of the collapse of the Soviet Union. Return to Cold War Events