1989: Warsaw Pact began to dissolve

The six Warsaw Pact countries of Eastern Europe, while nominally independent, were widely recognized as the Soviet satellite states. All had been occupied by the Soviet Red Army in 1945, had Soviet-style socialist states imposed upon them, and had very restricted freedom of action in either domestic or international affairs. Any moves towards real independence were suppressed by military force – in the Hungarian Revolution of 1956 and the Prague Spring in 1968. Gorbachev abandoned the oppressive and expensive Brezhnev Doctrine, which mandated intervention in the Warsaw Pact states, in favor of non-intervention in the internal affairs of allies – jokingly termed the Sinatra Doctrine in a reference to the Frank Sinatra song "My Way". Poland was the first republic to democratize following the enactment of the April Novelization, as agreed upon following the Polish Round Table Agreement talks from February to April between the government and the Solidarity trade union, and soon the Pact began to dissolve itself. The last of the countries to overthrow Communist leadership, Romania, only did so following the violent Romanian Revolution.