WARSAW — For all that Poland has accomplished since the fall of the Iron Curtain, it has long resisted fully coming to terms with its Communist past — the oppression, the spying, even the massacres. Society preferred to forget, to move on.

So it may come as a surprise that Poland and many of its neighbors in Central and Eastern Europe have decided the time is right to deal with the unfinished business. Suddenly there is a wave of accounting in the form of government actions and cultural explorations, some seeking closure, others payback.

A court in Poland last month found that the Communist leaders behind the imposition of martial law in December 1981 were part of a “criminal group.” Bulgaria’s president is trying to purge ambassadors who served as security agents. The Macedonian government is busy hunting for collaborators, and Hungary’s new Constitution allows legal action against former Communists....

Reconciling with the past is an issue that has hovered over post-Communist Europe for decades. But today that experience has broader global resonance, serving as a point of discussion across the Arab world where popular revolts have cast off long-serving dictators, raising similarly uncomfortable questions about individual complicity in autocratic regimes....