As a student at the University of Wisconsin in the late 1960s, documentary filmmaker Errol Morris demonstrated against the Vietnam War, and in particular the U.S. secretary of Defense, Robert McNamara. Under John F. Kennedy McNamara had defused the Cuban missile crisis and persuaded the president to withdraw from Vietnam. Then Kennedy was assassinated and McNamara, who stayed on under President Lyndon Johnson, implemented the escalation of the Vietnam War. A decade ago, in his memoir "In Retrospect," McNamara confessed the decision to wage war in Vietnam was "terribly wrong." Morris was intrigued. Known for his tough interviewing in films like "The Thin Blue Line," he recently directed a new, devastatingly frank documentary about McNamara, "The Fog of War." The film, which opens in Europe this week, is startlingly prescient and has already won several U.S. awards. NEWSWEEK's Dana Thomas recently spoke to Morris. Excerpts:

What do you hope to achieve with this movie?

I suppose I wanted to make an antiwar film. I don't like antiwar films that tell us the obvious: that war is bad. I wanted to tell a much more specific story about conflict--about people blundering into wars, about people having to make decisions based on expedience that will carry enormous ethical weight. I am interested in certain ironies--like the fact that he's talking about 40, 60 years ago, and for all intents and purposes he could be talking about last week. There is something horrific about the idea that nothing really has changed.

Did you think the film would be so relevant to what's going on today?

Not really. I started it before September 11. But it is becoming more topical day by day, particularly the notion of "preventative war." McNamara's first childhood memory is of Armistice Day, the war that Wilson described as "the war to end all wars," the ultimate preventative war. And what followed? The worst carnage known to man. War doesn't prevent war. War leads to more war. And if we have not learned that from the past, I don't know what will teach us.

How do you see McNamara in the context of American history?

He's like Zelig, only he wasn't just a peripheral character who shows up at opportune historical moments. He's actually an important figure. And he's in all of these moments--he's even there with Jackie, looking for a gravesite for JFK.

Was the death of Kennedy the true turning point in McNamara's life?

I think yes. Loss of innocence, a feeling of things spiraling out of control. His destiny [was] changing in ways he could not control.

Why is McNamara the only figure interviewed in the film?

I didn't want to make a standard historical documentary. It is McNamara reckoning with his own history, and himself. He says something very interesting, and by and large it's true. He says, "I was part of the mechanism."

The Nazis said that.

A lot of people say that. But he raises a very interesting question: what makes a war immoral if you lose, and moral if you win?

Do you see parallels between the McNamara period and today?

To me history is like the weather; it's always different, but there are themes that appear again and again. Is this exactly like the '60s? No. But are there things going on now that remind me of the '60s? Yes. The Aug. 4, 1964, Gulf of Tonkin attack that never happened--how similar is that to the weapons of mass destruction that everyone knew were certainly in Iraq and have yet to be found?

Where do you think [the Iraq conflict] will lead?

I don't know. For a long time, people--including myself--couldn't understand why, if McNamara was against the war, he didn't resign or speak out against it. But in the last two weeks we've been treated to a spectacle of what happens when you do, with [former U.S. Treasury secretary Paul] O'Neill speaking out against the policies of the Bush administration and the administration immediately responding by trying to marginalize and discredit him. In the end you wonder: what good does it do?

How would you describe current American foreign policy?

We've moved into a videogame era in foreign policy. People may not tolerate shades of gray very well, but it's become even more polarized, good versus evil, in those kinds of religious terms. There's an absolute inability to look at subtlety of any kind, and that is dangerous. The [U.S.] foreign policy at this moment is self-righteousness. Someone asked me the day after Saddam was captured what I thought about it. I said, "They have finally succeeded. All the complexity of a country has been reduced to something grotesquely simple: capturing one man. Just like in a videogame."