In the fall of 2002, during the run up to the war in Iraq, Oprah Winfrey devoted a portion of one of her shows to answering a pressing international question. Do the Iraqi people want America to liberate them from Saddam Hussein?

Ms. Winfrey posed the question to Entifadh Qanbar, a spokesperson for the Iraqi National Congress—an erstwhile group of Iraqi exiles led by Ahmed Chalabi that, at the time, was busy lobbying the American government to overthrow Saddam Hussein. “Absolutely,” responded Mr. Qanbar.

Later, Ms. Winfrey called on an audience member. “I hope this doesn’t offend you,” said the young woman. “I just don’t know what to believe with the media and…” Ms. Winfrey cut her off. “We’re not trying to show you propaganda,” Ms. Winfrey explained. “We’re just showing you what is.”

Four-and-a-half years later, with American troops embroiled in a seemingly intractable civil war in Iraq, and the reputation of Iraqi National Congress in tatters, the question of what exactly Ms. Winfrey and the rest of her colleagues in the media were showing to millions of American viewers on the eve of invasion begs a second look.

Tonight at 9:00 p.m., PBS will be airing a special episode of Bill Moyers Journal, entitled, “Buying the War,” which takes a long, hard look at the American media’s performance in the months leading up to the start of the war. The result is a detailed portrait of media groupthink gone horribly awry.

Throughout the 90 minute program, a large number of print and broadcast journalists--from Oprah, to Judith Miller, to George Will, to the Sunday morning talk show pundits, to Roger Ailes’ legions at Fox, to William Kristol, to the reporters on the evening network news, to Vanity Fair’s David Rose—are shown passing along hyperbolic stories about Iraq’s biological and nuclear weapons capacity.

As it turns out, many of those overblown stories relied almost exclusively on the false claims of hawkish administration officials and dodgy Iraqi defectors. Claims that often went unchecked by some of the best minds in the business.

There were exceptions, and throughout “Buying the War,” Mr. Moyers gives plenty of airtime to the reporters who got the story right, particularly to John Walcott, Jonathan Landay, and Warren Strobel of the erstwhile Knight Ridder news service.

The show also features captivating interviews with 60 Minutes’ Bob Simon, the Washington Post’s Walter Pincus, and an apologetic Dan Rather.

“Especially right after 9/11, especially when the war in Afghanistan is going on, there was a real sense that you don’t get that critical of a government that’s leading us in war time,” Walter Isaacson, the former chairman and CEO of CNN tells Mr. Moyers. “Big people in corporations were calling up and saying, ‘You’re being anti-American here.’”

Reached by phone on Monday, Kathleen Hughes, the producer of “Buying the War,” said that the documentary has been a year in the making. “Bill has called this a historical documentary except the history is only four years ago,” said Ms. Hughes.

“By and large most of us in the media accepted the administration’s point of view,” said Ms. Hughes. “I think that had to do with what some of our reporters say in the show--that there seemed to be an almost bipartisan belief that Saddam Hussein was keeping a big arsenal and that we had to be worried about him. But when you look at the Knight Ridder reporting you begin to understand that there was plenty of detailed, accurate information available in real time. That was the biggest surprise.”

Did the largely unflattering portrayal of the press leave Ms. Hughes feeling depressed about her profession?

“No,” said Ms. Hughes. “I still have a tremendous amount of respect for journalists. We all have our good work and our not so good work. I still think it’s a noble profession. Just look at the Knight Ridder guys. In this case, they’re my heroes.”