The end of the Cold War was also profoundly related to nationalism. As the Americans had learned through their experience in the Vietnam War, the Soviets came to realize, in the late 1980s, that it would be impossible to suppress nationalism in Eastern Europe or other parts of the world any longer, having recognized the intervention in Afghanistan as poor policy. This time, the Soviets had learned their lesson. Communism was not stronger than nationalism any more. Therefore, the Soviet Union resumed normal relations with China after a long rift and did not intervene in Eastern Europe when reform and independence movements ousted Communist governments in Poland, Hungary, and Czechoslovakia from 1989 to 1991.
The newly freed East European nations elected non-Communist governments, and East Germany also dissolved, becoming part of West Germany. Nationalist and independence movements having been active in the other republics, the Soviet Union also recognized the full independence of Estonia, Latvia, and Lithuania. Because of these nationalist movements, and perhaps because of the Soviet delay in realizing the importance of nationalism in these countries, the Soviet Union itself ceased to exist on December 21, 1991.
The end of the Cold War also brought about a temporary lull in the Cambodian civil war, which had been a sort of proxy war between China and Soviet-supported Vietnam. Since China was no longer an enemy of the Soviet Union, this proxy war was unnecessary as well. Almost all the Vietnamese troops having been pulled out of Cambodia, the warring parties signed a peace treaty in October 1991. They agreed that the UN and a Supreme National Council would govern Cambodia until a constituent assembly could be elected. Prospects for peace improved at least for a while.