'Yet we were wrong, terribly wrong. We owe it to future generations to explain why."

With those words, written nine years ago, Robert McNamara began an extraordinary final phase of his career -- devoted to chronicling the errors, delusions and false assumptions that turned him into the chief architect and most prominent promoter of the Vietnam war.

No historic figure has put so much effort into self-examination: At the age of 87, he has now written three very detailed and analytical books, and starred in one very good movie, devoted to the fundamental mistakes that led the United States into the most politically costly and least successful war in its history.

What, then, does he think about Iraq? Until now, the former secretary of defense has avoided comment on the actions of that job's current occupant, Donald Rumsfeld. The two are often compared to each other in their autocratic leadership styles and in their technocratic, numbers-driven approaches to war. And their wars, of course, are often likened. But Robert McNamara has insisted in staying out of the fray.

He decided to break his silence on Iraq when I called him up the other day at his Washington office. I told him that his carefully enumerated lists of historic lessons from Vietnam were in danger of being ignored. He agreed, and told me that he was deeply frustrated to see history repeating itself.

"We're misusing our influence," he said in a staccato voice that had lost none of its rapid-fire engagement. "It's just wrong what we're doing. It's morally wrong, it's politically wrong, it's economically wrong."

While he did not want to talk on the record about specific military decisions made Mr. Rumsfeld, he said the United States is fighting a war that he believes is totally unnecessary and has managed to destroy important relationships with potential allies. "There have been times in the last year when I was just utterly disgusted by our position, the United States' position vis-à-vis the other nations of the world."

On Monday night, we heard the United States at its very worst with George W. Bush's caustic State of the Union address, in which he declared, over and over, that America is serving God's will directly and does not need "a permission slip" from other nations since "the cause we serve is right, because it is the cause of all mankind."

That vision of manifest destiny, stripped of any larger view, has led down some unfortunate roads. The Iraq action, which would have been conducted in some form or another at some point under any imaginable government, would have been far better conceived if its executors had read Mr. McNamara's works instead of the Book of Revelation.

In 1995, in his memoir In Retrospect, Mr. McNamara published a list of the 11 specific mistakes he believed the United States had made in and around the Vietnam war that still had relevance in the very different political and military climate of the 21st century.

I have always been wary of comparisons between Vietnam and Iraq. The circumstances are profoundly different, and the scale of conflict and death is nowhere near the same. Vietnam was a small nation engaged in a civil war that Americans misread as a Chinese incursion on all of Asia, while Iraq has been strangled by one of history's worst totalitarian dictators. The American mistake was its belief that the dictator's removal would be sufficient.

But to read Mr. McNamara's 1995 list today is to read an uncanny analysis of the missteps of the Iraq campaign. He told me that this list has come to haunt him as he watches the Mesopotamian misadventure unfold.

Chief among the discoveries that led him to see Vietnam as a mistake, he said, was his realization that the United States could not, by itself, properly analyze the actions and ground-level conditions necessary to achieve the complex and ambiguous goals of a war -- reversing the influence of communism in Asia, in Vietnam's case, or bringing democracy to the Arab world, in Iraq's.

"And the reason I feel that is that we're not omniscient," he said. "And we've demonstrated that in Iraq, I think." He pointed to Washington's failure to appreciate the complexities of Iraqi culture, and therefore to anticipate the extended guerrilla war it is now engaged in -- a chief mistake of Vietnam. Without the full involvement of other major nations, he said, such mistakes will always be made.

"And if we can't persuade other nations with comparable values and comparable interests of the merit of our course, we should reconsider the course, and very likely change it. And if we'd followed that rule, we wouldn't have been in Vietnam, because there wasn't one single major ally, not France or Britain or Germany or Japan, that agreed with our course or stood beside us there. And we wouldn't be in Iraq."

In his recent book Wilson's Ghost, Mr. McNamara argued that military forces should sometimes be used to oust dictators guilty of grave crimes against humanity. However, he said, this can succeed politically and militarily only if it is done with broad international support under the aegis of a body such as the United Nations (which helped intervene in East Timor) or NATO (which led the charge in the Balkans).

"The United States is today the strongest power in the world, politically, economically and militarily, and I think it will continue to be so for decades ahead, if not for the whole century," he told me. "But I do not believe, with one qualification, that it should ever, ever use that power unilaterally -- the one qualification being the unlikely event we had to use it to defend the continental U.S., Alaska or Hawaii."

Mr. McNamara said it is particularly upsetting to see that the White House administration has ignored or failed to heed key recommendations coming from military officers on the ground in Iraq -- a crucial and oft-repeated mistake in Vietnam. American military officials in Iraq complained early that their forces were ill-equipped for the complex work of nation-building and policing, but the White House has until very recently refused to discuss using UN peacekeeping forces for such work.

Last week, the United States indicated that it is seeking the UN's assistance in the nation-building effort, a move that Mr. McNamara said is vital if the war is ever to be brought to an end, and civil life restored in Iraq.

"Many people, myself among them, thought the United Nations should have played a much greater role in connection with Iraq than it has, and I'm personally very pleased to see that the administration is thinking today of increasing the role of the UN. . . . I hope the UN will accept."

To appreciate the staggering scale of the lessons Mr. McNamara has learned, everyone ought to see the new feature documentary about him, The Fog of War. Its director, Errol Morris, is certainly the best non-fiction filmmaker alive (his Fast, Cheap and Out of Control is the most action-packed movie ever made about the philosophy of being). This film, focused tightly on the bombings of Japan in the Second World War and Vietnam in the 1960s, offers a profound fourth volume to Mr. McNamara's continuing mea culpa.

In it, he suggests repeatedly that his faith in superior military technology and the scientific potential of data processing (he was known to his 1960s critics as "an IBM machine with legs") led him to underestimate the difficulties and complexities of the cultures in which he was fighting.

The same fundamental fallacy, he said, is present today. Even though computerized and laser-guided weapons allow campaigns to be waged with only a few dozen American deaths and hundreds of foreign deaths (as opposed to the tens of thousands of American deaths and hundreds of thousands of Vietnamese deaths in the 1960s and 1970s), it has become no easier to achieve society-transforming military goals, or to extricate yourself from an invaded nation.

"The new circumstances and new technology didn't help us in Iraq, and the issue there was allegedly the risk of proliferation of nuclear weapons. You can't get anything more fundamental than that. The case for this was certainly made forcefully -- I think erroneously, but it was very well made. . . . And now we've just got to repair these fissures, these breaks in our relationship with many, many important powers in the world, and many important institutions."

He said many lives have been unnecessarily lost around the world because the United States has refused to support the International Criminal Court, an institution he believes could have provided an alternative to war in Iraq.

"Let's think about that in human terms -- you have to reduce the risk of killing and catastrophe," he said. "We've got to do that, and we're not paying nearly enough attention to it. And one illustration is, we don't support things that would have that as their goal . . . for example, this international court. The U.S. is totally opposed to it. I think they're absolutely wrong. We've not only refused to support it, we try to buy off countries that are supporting it."

Mr. McNamara broadly declined to discuss specific decisions made by Mr. Bush -- "I don't want to get in an argument with Bush and the administration. I don't think that advances my interests at all," he said. But he didn't mind adding that he was dismayed that members of the Republican administration have likened their position after Sept. 11, 2001, to that of John F. Kennedy during the Cuban Missile Crisis, which had been Mr. McNamara's moment of truth. Mr. Bush, he said, wouldn't have been up to it. And Mr. Kennedy would have handled Iraq differently.

Just over a year ago, Mr. McNamara traveled to Cuba and learned just how perilous that moment had been: Cuba, Fidel Castro admitted, had been home to a nuclear arsenal, and he had been willing to sacrifice his own island nation in order to launch a nuclear attack on the United States. The world really did come within moments of ending.

More than anything else, this revelation has led Mr. McNamara to argue that the Kennedy approach to the world ought to be emulated. Mr. McNamara was the first to argue, based on his own diary, that had he lived, JFK would have ended the Vietnam war in 1965.

I take that claim with a grain of salt, since I believe that Mr. Kennedy's record of endlessly reversing himself and caving in to the authority of his military commanders would have trumped his better convictions.

Nevertheless, recently declassified documents have lent the notion credence. And I do believe Mr. McNamara when he says that the Kennedy taste for international co-operation would have served the world better than the White House's current with-us-or-against-us approach.

"I don't believe that Kennedy would be reacting the way Bush is. For one thing, Kennedy reached out. A critic in those early days of the administration was John Kenneth Galbraith [the Canadian economist, who believed Vietnam was a bad idea]. And Kennedy reached out, and appointed him to a high-level position, and he talked to him about Vietnam. You don't see that today."

McNamara's 11 lessons

In 1995, former U.S. Secretary of Defense Robert McNamara published In Retrospect, the first of his three books dissecting the errors, myths and miscalculations that led to the Vietnam War, which he now believes was a serious mistake. Nine years later, most of these lessons seem uncannily relevant to the Iraq war in its current nation-building, guerrilla-warfare phase.

We misjudged then -- and we have since -- the geopolitical intentions of our adversaries . . . and we exaggerated the dangers to the United States of their actions.

We viewed the people and leaders of South Vietnam in terms of our own experience. . . . We totally misjudged the political forces within the country.

We underestimated the power of nationalism to motivate a people to fight and die for their beliefs and values.

Our judgments of friend and foe alike reflected our profound ignorance of the history, culture, and politics of the people in the area, and the personalities and habits of their leaders.

We failed then -- and have since -- to recognize the limitations of modern, high-technology military equipment, forces and doctrine. . . .

We failed as well to adapt our military tactics to the task of winning the hearts and minds of people from a totally different culture.

We failed to draw Congress and the American people into a full and frank discussion and debate of the pros and cons of a large-scale military involvement . . . before we initiated the action.

After the action got under way and unanticipated events forced us off our planned course . . . we did not fully explain what was happening and why we were doing what we did.

We did not recognize that neither our people nor our leaders are omniscient. Our judgment of what is in another people's or country's best interest should be put to the test of open discussion in international forums. We do not have the God-given right to shape every nation in our image or as we choose.

We did not hold to the principle that U.S. military action . . . should be carried out only in conjunction with multinational forces supported fully (and not merely cosmetically) by the international community.

We failed to recognize that in international affairs, as in other aspects of life, there may be problems for which there are no immediate solutions. . . . At times, we may have to live with an imperfect, untidy world.

Underlying many of these errors lay our failure to organize the top echelons of the executive branch to deal effectively with the extraordinarily complex range of political and military issues.