A few days ago, I discussed the anniversary of West Germany joining NATO. Today is the anniversary not of a free nation joining a military alliance of its own accord, but of a puppet state joining a hegemony. The Warsaw Pact was created to ensure Soviet control over Eastern Europe as democracy and capitalism became entrenched in Western Europe. The immediate cause of the formation of the Warsaw Pact was West Germany joining NATO. The Soviets were still recovering from the damage from the German invasion and the losses they suffered invading Germany. They saw the acceptance of West Germany into NATO as the United States and Britain allying with the enemy and building an alliance against the Soviets. The Soviets realized that they would be unable to force the Allies out of Germany after the failure of the Berlin airlift, and so their goal became to maintain their control over the nations that had fallen behind the curtain after the Second World War. To this end, they invaded multiple members of the Warsaw Pact that attempted to institute policies counter to Soviet interests and ideology. Most famously, they invaded Czechoslovakia in 1968 but Hungary was invaded in 1958 as well. East German support to the former effort was minimal however, and the nation was one of the more independent members of the Warsaw Pact. That being said, the Pact was still unpopular among the population and was quickly exited once the Communist government in East Germany fell. Once the nation untied with West Germany it too was incorporated into NATO, along with all of the other former Warsaw Pact nations.
For over forty years, the Warsaw Pact stood as a symbol of authoritarianism in Europe. Its fall would remove one of the major products of World War II, namely Soviet dominance in Eastern Europe. The independence of not only East Germany but Poland, Hungary, and a dozen nations which were either former soviet puppets or formally part of the Soviet Union. The Soviet Union replaced one overlord with another, and its its fall would bring an end to half a century of subjugation.