The map of Europe at the end of WWI had never intended to be permanent, but the new Cold War between the Soviet Union and America (and by extension the democratic and capitalistic West) had led to the divisions in Europe and Asia being an established part of the geopolitical landscape.

Detente was a doctrine in the 1970s which accepted those divisions and map as permanent. This gave the Soviet government legitimacy, as well as the territory and political hold they had on Europe legitimacy as well. Detente was more important to the Soviets than it was America, however, from the US point of view it followed a doctrine of realpolitik.

John Lewis Gaddis points to several world leaders who were not prepared to deal in Dentente which entrenched the cold war conflict as the status quo; they were Ronald Reagan, Margaret Thatcher, Pope John Paul II, Lech Walesa and Mikhail Gorbachev. (more)

When Czechoslovakia threatened to transition to democratic capitalism Leonid Brezhnev implemented what came to be known as the Brezhnev Doctrine; the USSR could violate the sovereignty of any country in which an effort was being made to replace Marxism-Leninism with capitalism. Beware the morally unassailable courtesy of ideology when they have the resources of a nation-state behind them. (more)

After World War II when the conflict between Stalin's ambitions and American wishes to hand Europe back over to the Europeans, the Americans found they had to face Stalin flatly. After confusion as to Stalin's behaviour Truman denied territorial concessions in Turkey and the Mediterranean. Additionally the US Sixth Fleet was stationed in the Mediterranean permanently and indefinitely.

Stalin did not conduct foreign policy through the European great power policies or Realpolitick; instead his policies were ideological and stemmed from a Marxist reading of capitalism being inherently at war with itself and unsustainable. Stalin believed democracies were the same and in short order America, Britain and France would all be at war with each again.

To explain all this George F. Kennan sent a 'long telegram' of 8,000 words from the embassy in Moscow to the US. Telegrams at the time were short as the technology was laborious and had bandwidth issues. Kennan's telegram broke with accepted conventions but ended up informing Truman's policy of containment and the Marshall Plan. (more)

Stephen Cohen has an article titled; The New Cold War . Cohen argues that the main threat to American security remains Russia and that the American policy approach to Russia since the Cold War is exacerbating that threat. (more)