PARIS — A nation's relationship with its past is crucial to its present and its future, to its ability to "move on" with its life, or to learn from its past errors so as not to repeat them. This includes the past that isn't dead and buried — "in fact, it is not even past," as William Faulkner famously said. Such a past obsessively blocks any possible evolution toward a necessary reconciliation with oneself and a former or current foe.

Such a past is painfully visible today, for example, in the Balkans, a region largely paralyzed by a painful fixation on the conflicts that tore it apart in the 1990s. An absolute inability to consider the point of view of the other and to go beyond a sense of collective martyrdom still lingers over the entire region.

What the Balkans need nowadays are not historians or political scientists, but psychoanalysts who can help them transcend their past for the sake of the present and the future. It is to be hoped that the promised entrance into the European Union will constitute the best "psychoanalytical cure."

In contrast to this paranoid version of the past is a past that is buried under silence and propaganda; a past that is simply not dealt with and remains like a secret wound that can become reopened at any moment. Of course, nontreatment of the past is not the exclusive privilege of nondemocratic regimes.

More than 30 years after the end of the long dictatorship of Francisco Franco, Spain finds itself confronted by the shadows of a past it has deliberately chosen not to confront. That supposedly buried past was always there, poised to erupt with a vengeance once the economic miracle slowed or stopped.

China, which has just been celebrating with a martial pomp the 60th anniversary of Mao's founding of the "People's Republic," constitutes one of the most interesting cases of a nation evincing "shortsightedness" toward its past.

China has a lot to show for in its recent history. Just consider the massive access to education of its huge rural population in contrast with its "democratic rival" India. China's pride nowadays is legitimate.

In 60 years a weak and divided country, torn apart by wars internal and external, has arrived at the point where it is about to become the second most powerful economy in the world. China's prosperity (even if it is far from being distributed equally) and relative political stability (even if the regime remains open to a strictly limited degree) are undeniable and deserving of respect. But the success of a country that has so mobilized its energies as to transform past humiliations into massive national pride is not accompanied — and this is an understatement — by a responsible exploration of its past.

China endured two hideous decades between 1957 and 1976, from the beginning of Mao's "Great Leap Forward," which led to a mass famine that killed tens of millions of people, to the end of the "Cultural Revolution," which left Chinese society divided and traumatized due to its wanton cruelty and the destruction of cultural goods. China must confront this period if it wants to progress domestically and become a respected and respectable actor in the international system.

But how can China become capable of implementing the "rule of law" that it so badly needs, let alone democracy, if it continues to systematically lie to its people about the recent past? To refuse to deal with a painful past is to risk reproducing it.

Such a choice can encourage the most dangerous nationalist tendencies within a society whose citizens, especially the young, do not know what hides behind the silence and official lies. The Chinese students I taught at Harvard last year ignored almost completely their recent history. They reacted with a somewhat "defiant nationalism" to critical observations. They were going "to check" the "accuracy" of historical remarks that did not fit with the history they had been taught at school. How could I be so critical of Mao? It demonstrated my Western bias against a rising Asian giant.

Between the two extreme of the Balkans and China, the relationship between "Memory" and "History" knows many shades of gray. It took France nearly 50 years to openly confront its Vichy past and to recognize that the French state had been guilty of collaboration with the Nazis. The country's colonial past still remains a painful issue that is far from being confronted in a dispassionate, objective manner. It is as if truth and justice are seen as potential obstacles to peace, stability and progress.

But there is a major difference between the search for historical truth, which is an absolute must for society at large, and the quest to settle scores and punish those found and declared guilty. One must know the past not only to avoid repeating it but also to transcend it.

Between a history that paralyzes a nation's ability to "move on" collectively and an unwillingness to face the past, which can lead to criticism of the present, there is ample room in which to maneuver. Healthy nations use that room to bury the pain of the past, if not the past itself.

Dominique Moisi is Visiting Professor of Government at Harvard and author, most recently, of "The Geopolitics of Emotion." © 2009 Project Syndicate (www.project-syndicate.org)