This week’s international commemorations of the 60th anniversary of the liberation of the Auschwitz death camp – at the United Nations and at the camp itself – were attended by leaders from around the world. National commemorations – in the United States, Britain, Germany, France, and many other countries – were also held, with other dignitaries, including Queen Elizabeth, in attendance. The admonition heard at virtually all of them is the one that has been uttered repeatedly since the time of the Holocaust – “Never again!”

Yet the world’s experience with genocides during the decades since Nazi Germany set out to murder every Jew it could find mocks this venerable pledge. After each genocide, the government leaders who could have stopped it but failed to do so, and even those who obstructed the efforts of others to stop it, have said “Never again!” – with the “never” to start, finally, with that particular genocide. Have we learned nothing from this tragic history – and are we, as Santayana famously warned, eternally condemned to repeat it?

A glance back at the genocide in Rwanda starkly illustrates the pity of it all.

In the spring of 1994, the Hutu-controlled army, as well as Hutu militias, in an effort to exterminate all Tutsis, hacked some 800,000 of them to death. Very early in the course of the genocide, high State Department and White House officials knew very well what was happening – and not only did nothing to stop it but did all they could to stop others, including the U.N., from stopping it.

And for a long time they refused to call what was happening a genocide, fearing that, if they did, that would commit the American government, under the Holocaust-inspired 1948 Genocide Convention, to, as an internal memo put it, “actually ‘do something.’ “

Six years after that genocide, a member of a panel set up by the Organization of African Unity to investigate how it could have happened while the world stood by said, at a press conference, “The United States … knew exactly what was going on. …I don’t know how Madeleine Albright lives with it.” Asked about that comment, Secretary of State Albright, who had been America’s ambassador to the U.N. during the genocide, said that, at the time, she had “followed instructions.” Her bosses, Secretary of State Warren Christopher and President Clinton, knew, or should have known, very early during the genocide, its scope and magnitude – but set the tone and policies that the administration followed. Later, visiting Kigali, Rwanda’s capital, Mr. Clinton apologized for not appreciating the genocide’s depth and speed and for not immediately calling it a genocide and not immediately acting.

If anyone high in the White House or the State Department didn’t know what was happening it was because they didn’t want to know. No one wanted a repeat of the peacekeeping debacle that had occurred in Somalia six months earlier. Officials assumed that, somehow, things would settle down – and they focused their attention elsewhere.

How to square this with Mr. Clinton’s sensitivity, expressed before and after the Rwanda genocide, to the lessons of the Holocaust? How to square it with his statement at the opening of the United States Holocaust Memorial Museum in 1993, in which he expressed sorrow that, before World War II had started, “doors to liberty were shut”? And how to square it with his message to an international Holocaust conference in 2000 in which he said, “We must never forget what happened when governments turned a blind eye to grave injustice outside their borders, when they waited too long to act”?

And what about Mr. Christopher’s directive – well over a month into the killings, and long after human-rights organizations had begun calling it a genocide – that the killings should be termed only “acts of genocide”? How can that be squared with his appreciation of the lessons of the Holocaust? I stood next to him in 1996, at an exhibit on Capitol Hill about a young American, Varian Fry, who, in southern France, had saved some 2,000 human beings from the Holocaust’s maw despite opposition and harassment from the State Department. “Frankly,” Mr. Christopher said at the time, “the conduct of our department was not our finest hour.” Five months earlier, planting a tree in honor of Fry at Israel’s Yad Vashem Holocaust memorial, Mr. Christopher had said that we owed Fry “a promise to do whatever is necessary to ensure that such horrors never happen again.”

Clearly, when it comes to past history – to the Holocaust – it is, for leaders, “Never again!” But when the “again” arises again, and rescue poses difficulties, rationalizations are summoned that lay the ground for inattention and willful ignorance and that justify delay and even obstruction.

At the U.N. commemoration this past week, Secretary-General Kofi Annan said, “On occasions like this, rhetoric comes easily.” And he added: “We rightly say, ‘Never again.’ But action is much harder. Since the Holocaust the world has, to its shame, failed more than once to prevent or halt genocide.” Mr. Annan should know, the U.N. having been criticized for its own inadequate response to the Rwanda genocide.

So what’s the use of Holocaust commemorations? Aren’t the leaders who attend them, and who solemnly and insistently utter the words “Never again!” likely, when actually faced with a another genocide, to look elsewhere?

Maybe, but I’m not ready to give up on the power of Holocaust commemorations to influence behavior.

For one thing, despite their post-Holocaust failures to respond to genocides, I’m not ready to give up on the possibility that, eventually, we’ll do what needs to be done when genocide begins, or is even threatened. Even politicians and diplomats, accustomed to public utterances and to reading speeches written by others, can be touched by the words they emit. And public acknowledgments of past depredations and inactions are immensely important.

No less important, though, is the fact that Holocaust commemorations, if done right, let us get beyond abstractions – beyond the concept of genocide and the incomprehensibility of large numbers of victims – to focus, also, on the individual victims. It’s this kind of focus that can get under the skins of leaders, into their souls, and, with luck, into their minds, so that they’ll finally remember the “again” before, not after, it happens.

Most of the 60th anniversary commemorations attended by heads of state have been accompanied by exhibitions about the Holocaust – including the images and stories, more powerful than any abstractions and pledges, of individual victims.

At Auschwitz, the visiting world leaders, including Vice President Cheney, the head of the American delegation, were confronted by enlargements of photos from a set taken there by the Germans in May of 1944, during the arrival of transports of Hungarian Jews. Those photos are placed exactly where they were taken 60 years ago in order to show what happened there as the Jews moved through the extermination process – the disembarkation from the transports, for example; the selection of some to work and of most, deemed “not fit to work,” to be gassed; the unknowing walk by victims toward the gas chambers, with a building housing one of those gas chambers and its cremation ovens looming menacingly behind them.

One of those photos is installed in front of the remains of another of the gas chamber buildings; it’s of Jews – mostly elderly men, women and children – who, a few minutes after the camera’s shutter was snapped, would be ordered to undress and get into the building for “showers.” Four young girls, including a girl of 4 or 5 with clasped hands, stare into the camera’s lens. Larry Rivers, the American artist, saw that photo and painted the scene on a large canvas. When I was the director of the United States Holocaust Memorial Museum, I hung that painting on the wall facing my desk so that I’d never forget the individuals for whom that museum was a memorial – and each morning those young girls would make eye contact with me. This past week, in Auschwitz, staring out from the same photo planted in the ground in front of the gas chamber in which they were gassed, those girls were able to make eye contact with world leaders.

One day, while I was the Holocaust Museum’s director, a visitor to the museum, an Auschwitz survivor, looked at another photo from that set, which is on the wall of the museum’s permanent exhibition. It’s a photo of Jews getting out of cattle cars and lining up for selection. The visitor was convinced that, in the photo, she saw herself, her mother, and her baby daughter. She also said she saw the prisoner who had told her that it would be better if she were to hand her baby to her mother. Confused and uncomprehending, she did that. That act, it turns out, saved her life. Had she not given the baby to her mother, all three would have been killed, since women holding babies were automatically sent to be gassed, as were older women, such as her mother. Having given her baby to her mother, she was ordered to move to the line that turned out to be for those who were “fit to work” – and only her mother and baby were sent into the other line, the one that was destined, she later learned, for the gas chamber. When she saw the image of her child on the Holocaust Museum’s wall she broke down. Sobbing, she said it was the only picture that existed of her child. She touched it, caressed it, wouldn’t leave it. The other museum visitors nearby also broke down and wept, and so did a staff member. This was the Holocaust summarized in a single story contained in a single photo.

These are the kinds of personal, human stories that world leaders were able to witness during their participation in these week’s commemorations. They may not have known the full stories behind the photos, but the photos were stories in themselves. Photos from the set taken at Auschwitz were displayed not only in Auschwitz but also at the exhibition at the U.N. that was installed by Israel’s Yad Vashem Holocaust memorial to accompany this week’s commemoration.

It’s individual Holocaust stories – the kinds displayed in photos, memoirs, diaries and survivor testimonies – that, more than abstractions about genocide or the Holocaust, can teach us about the vulnerability each of us has to becoming a victim – even a victim of genocide. And it’s individual Holocaust stories that, more than routinized pledges of “Never again!” can teach us about the vulnerability each of us has, especially those of us who are leaders and are asked to act when action is hard, to look away from the victimization of others and to justify, with endless bad reasons, again and yet again, our failure to save them.

Mr. Reich, a psychiatrist, is the Yitzhak Rabin Memorial Professor of International Affairs, Ethics, and Human Behavior at George Washington University and a senior scholar at the Woodrow Wilson Center. He was the director of the United States Holocaust Memorial Museum from 1995 to 1998.