A new parliamentary proposal to establish a commemoration day in honor of those Germans expelled from Eastern Europe following World War II has revived an ongoing debate about Germany's 20th century history. Dozens of accomplished academics have blasted the idea in an open letter.

To an outsider, it could almost seem like just another item on a packed parliamentary calendar. Last week, Germany's federal parliament, the Bundestag -- led by Chancellor Angela Merkel's conservatives and her business-friendly coalition partners, the Free Democrats -- voted in favor of a proposal which could lead to the addition of another commemoration day to the German year.

But the event up for commemoration is anything but free of controversy. The day, should Merkel's cabinet choose to pursue the idea, would be in memory of the expulsion of millions of Germans from Eastern Europe in the wake of World War II. Past efforts to commemorate their suffering have reliably elicited outcries from both within Germany and abroad. Portraying Germans as victims of World War II, after all, is always a dicey proposition.

The Berlin opposition took the lead last week in blasting Merkel's conservatives. On Monday, they were joined by 68 leading historians from Germany and elsewhere in Europe, who published an open letter criticizing the idea.

Parliamentary support for such a commemoration day, the document reads, is "an incorrect historical-political signal."...