Willy Brandt, then Chancellor of West Germany, falls to his knees at the memorial to the Warsaw Ghetto in 1970: This spontaneous gesture was the most powerful and moving image of German repentance of the whole postwar era 

Dear Günter Grass,

First: why an open letter? I have never written one before, whereas you have written dozens. You are, so to speak, Europe's leading man of open letters. I admit that the idea of turning the tables on you did appeal to me.

But there is another, more personal reason for my decision to address you in this way. In a newspaper interview about your autobiography, Peeling the Onion, you have admitted, after 60 years, that you belonged to the Waffen SS. I want to make you aware of my feeling of betrayal —a feeling I believe I share with most of your countrymen. And I want to show solidarity with the victims, living and dead, of the regime you tried so hard to prolong.

A public intellectual like yourself is, of course, entitled to preserve a private sphere. But there are certain biographical facts about which it is necessary to be open, as I am sure you would agree. You do not need me to tell you that, for a German of your generation, frankness about your activities during the Third Reich is not merely a moral imperative, but a sine qua non for any kind of public role.

Let me first recall a memorable scene in 1970: Willy Brandt falling on his knees at the memorial to the Warsaw Ghetto. It was the most moving and powerful image of German repentance of the whole postwar era. You were there at his side, representing German culture, as the German Chancellor went to sign his historic treaty with Poland and made his spontaneous gesture of atonement for the Holocaust.