The United Germany No One Saw Coming
When the Berlin Wall came down, experts such as Alfred Grosser -- a French teacher of German history -- believed that German reunification was a fantasy that would never happen, for a number of reasons. East Germany had acquired a distinct identity, "Prussia" was culturally very different from the Western Länder, and the Soviet Union didn't want it.
When reunification became certain, the same experts explained that Kohl's mistake was going to cost him the next election. When the election took place in March 1990 and Kohl's CDU crushed Lafontaine's SPD in both Eastern and Western Länder, the same experts decided to refer to the reunification as the "unification". Germany, in their opinion, had never been unified; nevermind the Holy Empire, the Second Reich or the Weimar Republic. Or even the Third Reich, actually.
Finally, when "unification" didn't stick and reunification was already old news, the myth that the reunification was the distant outcome of the failed Ostpolitik -- the German détente, initiated by Willy Brandt's Social Democrats in the 1970's -- started to spread.
The truth is that Germany's division was only made possible by the Soviet occupation. But it lasted long enough to look like the normal state of things, just as Europe's division did. Most people, including the experts, were completely unable to imagine any other situation. Days before the Wall was opened, as thousands of East Germans were already pouring to the West through Hungary, the division of Europe was still thought of as unshakable. And let us not even mention the Soviet Union.
The mental process of rationalization played its part. All kinds of reasons such as those mentioned above were used to justify this state of things. A world without the Eastern Bloc, the Soviet Union and the GDR was so difficult to imagine that it had to be justified by more than the Soviet occupation.
Finally, a Sovietless world was also seen as very frightening. There were some good reasons for that, but overall, most people were essentially conditioned to accept the political order as it was. Wishing for it to change was seen as unrealistic and irresponsible. This is probably the main reason why the Cold War wasn't exactly won by the West: the West didn't want to, or at least most people seemed to view some sort of negotiated settlement as much more preferable than what finally happened.
Except maybe for the Germans who revealed themselves as much keener to reunify than they had previously seemed. Backed with huge support by Germans from both sides of the former Iron Curtain, Kohl was able to play his part very efficiently. He made it very clear that he was asking for Soviet permission essentially out of courtesy. What he gave in exchange for the Soviet agreement was a symbolic face-saving concession: the recognition of the Oder-Neisse line as the German-Polish border. So both Germany and the Soviet Union conceded on matters they couldn't do anything about, and the matter was settled.
There are essentially two lessons here. First, totalitarian regimes hide their weaknesses well. East Germany had no substance, only Soviet tanks were keeping it together, but the West didn't see it. Likewise, the Soviet Union fell apart much more easily than anyone would have thought.
Second, no one knows when a totalitarian regime will fall apart, and no one can do much about it. During the final phase of the Cold War, Western powers essentially did their best to keep the Soviet Union in place. They supported Mikhail Gorbachev any way they could, ignored Yeltsin until the August 1990 coup, and failed to give much support to the Lithuanian independence movement. The Soviet Union's demise was a completely autonomous process in which the West played no part. But the Soviet collapse still took place and no one could do much about it.
This is what makes it particularly silly to keep the same kind of illusions about North Korea today. The Korean peninsula is divided in much the same way as Germany was. Many experts make the same kinds of rationalizations as their predecessors did about Germany: China and Japan don't want a "big" Korea, the U.S. will want to keep a military presence there (and a divided Korea gives them a pretext), South Korea believes reunification would be too expensive and so on.
That sounds a lot like the mistakes we made in the 1980s. First, these points are not very convincing in themselves. The U.S. doesn't have any real interest in keeping thousands of soldiers in Korea when they could be very useful elsewhere. China could probably obtain a denuclearized Korea if reunification took place. Japan may be pleased not to be the only democracy standing up to China. And how in the world could South Korea not want to get bigger when it is facing neighbors like China and Japan? As for the economic costs of uniting two Koreas, they will be huge indeed, but that will probably not keep 90% of South Koreans and 100% of the North Koreans from demanding reunification.
And most importantly, whose decision will it be? As soon as the North Korean army, for any kind of reason, stops shooting people who try to sneak through the DMZ, the regime will be over and no one will be able to do anything about it. The South Koreans will not likely shoot refugees in order to keep them in the North, so the choice will be between a reunification within South Korea or in the whole peninsula. Plans for a huge humanitarian operation in the North may be devised, as they apparently are, but that will not change the final outcome, which will be the reunification of both Koreas.
When that happens, we will know if we have learned anything from the German reunification.