...Two years ago, the 20th anniversary of the fall of the wall was celebrated by the German government with guests from all over Europe. A ceremonial toppling of giant dominoes was meant to represent the fall of Communism across Eastern Europe.

This is a darker moment to recall, the morning of Aug. 13, 1961, when Berliners awoke to find that soldiers had erected barbed-wire barricades, closed down road traffic and sealed off rail links between East Berlin and West Berlin. To this day, the memory dredges up unresolved issues. Germans have never quite come to terms with the building of a wall that sundered their city for 28 years, forging a border where Germans shot Germans for trying to travel across town.

The degree of ambivalence about the fall of Communism and the end of the East German state was evident in a survey published by the daily newspaper Berliner Zeitung, in which a third of Berliners thought that the building of the wall was either justified or partly justified to stem the tide of refugees leaving for the West....