Immediately after the report aired, Internet commentators, or bloggers, such as powerlineblog.com and littlegreenfootballs.com, began to question the documents' authenticity. Several newspapers also conducted their own investigations that questioned the authenticity of the documents.

CBS initially defended its reporting, but later issued an apology and aired follow-up broadcasts intended to clarify the use of the documents, while at the same time insisting that the gist of the report was true.

On Jan. 10, 2004, the network asked three CBS executives to resign and fired a fourth following the release of an independent report saying "myopic zeal" led to the flawed report on President Bush's military record. (Requires Adobe Reader)

CBS News anchor Dan Rather had already said, in November, that he was planning to retire in March 2005 but that the decision was not connected to the fallout from the National Guard report.

What Went Wrong

"Oh, I would describe it as preferential treatment. There were hundreds of names on the list of people wanting to get into the Air National Guard or the Army National Guard," Barnes, who was also a fund-raiser for Mr. Bush's 2004 Democratic opponent, said on the broadcast. "I think that would have been a preference to anybody that didn't want to go to Vietnam, that didn't want to leave. We had a lot of young men that left and went to Canada in the '60s and fled this country. But those that could get in the reserves or those who could get in the National Guard, chances are they would not have to go to Vietnam."

The report presented documents, now linked from CBS' Web site:
May 4, 1972
May 19, 1972
Aug. 1, 1972
Aug. 18, 1972
purportedly written by Lt. Col. Jerry Killian, Mr. Bush's commander at Ellington Air Force Base in Houston, that dealt with the president's missed physical exam and his request to transfer to Alabama so he could work on a campaign for his father, who was then a congressman of Texas.

The documents describe how George W. Bush approached him about getting a transfer to Alabama to work on a campaign for his father and how the younger Bush failed to undergo a required physical exam.

The day after the broadcast, neither President Bush nor his challenger Sen. John Kerry, D-Mass., mentioned the 60 Minutes report during campaign stops, instead focusing on their plans for trade and health care, respectively.

Democratic politicians, however, picked up on the report and demanded answers from Mr. Bush. White House spokesmen, calling the story a recycled attack timed to discredit President Bush, said the president fulfilled his obligation to the National Guard and was honorably discharged, a point no one has disputed.

Meanwhile, challenges to the documents' authenticity began appearing on Internet bulletin boards, including comments from self-described experts, some with Republican ties, according to Reuters.

Document experts said the memos were not produced on a typewriter in 1972 and 1973 but on a computer at a later date.

Killian's former wife and son also questioned their authenticity. Killian is deceased.

Newspapers, such as The Washington Post and The Dallas Morning News, conducted their own investigations and found problems with the memos.

A raised "th" or superscript had not been installed in typewriters by the year they were purportedly written, the news reports said. But Rather said some models of typewriters did contain the superscript as evidenced by other military memos released by the White House dating back to 1968, according to an update posted on the network's Web site.

Other reports said the drafter of one memo used the acronym OETR, which is an Army rather than National Guard term, and might have meant OER, or Officer Effectiveness Report.

And a National Guard officer cited in one of the documents as exerting pressure to "sugar coat" Mr. Bush's record had retired a year and a half before the date on the memo, The Dallas Morning News reported.

But the most decisive evidence came on Sept. 15, when The Dallas Morning News published an interview with Killian's secretary, Marian Carr Knox, who said she did not type the memos, although she typed similar ones for her boss.

"These are not real," she told the newspaper. "They're not what I typed, and I would have typed them for him."

But she said the content was accurate. "I remember very vividly when Bush was there and all the yak-yak that was going on about it."

Knox said she did not support Mr. Bush as president, calling him "unfit for office" and "selected, not elected," the newspaper reported.

CBS spokeswoman Sandy Genelius said at the time, "As far as we can tell, this individual is not a documents expert. We believe the documents, which were one part of the 60 Minutes story, to be genuine. It is notable that she confirms the content of the documents, which was the primary focus of our story in the first place."

The network said the documents were screened by experts who said they were typed in the 1970s. CBS News' Web site posted letters from two document experts who supported the memos' authenticity.

CBS News President Andrew Heyward said the same day The Dallas Morning News published its Knox interview that the network "would not have put the report on the air if we did not believe in every aspect of it." However, he also said CBS News would try to resolve "unresolved issues" related to the report.

"Enough questions have been raised that we're going to redouble our efforts to answer those questions," Heyward said.

Knox appeared on 60 Minutes that night with Rather, telling him she did not type the documents but their content was true.

Republican lawmakers, meanwhile, had come out full bore against the original report. House Majority Whip Roy Blunt, R-Mo., said he collected signatures from 39 colleagues on a letter sent to the network calling for a retraction and demanding CBS News to reveal the source of the documents. And Rep. Chris Cox, R-Calif., asked the House Subcommittee on Telecommunications and the Internet to investigate the matter.

CBS on Sept. 15 responded in a statement, citing long-standing journalistic practices of protecting confidential sources.

Rather, still standing by the thrust of the report, said on a follow-up 60 Minutes broadcast: "We will keep an open mind and we will continue to report credible evidence and responsible points of view as we try to answer the questions raised about the authenticity of the documents."

Susan Tifft, professor of journalism and public policy at Duke University, said on the Sept. 16 NewsHour that the impact the report has on CBS depends on how the network handles it from here:

"CBS and Dan Rather in particular are really sort of the poster children for all the charges of bias, left-wing bias in the media, so I think CBS in particular is very much, you know, not on the ropes exactly, but certainly the focus of a great deal of attention. And people inside CBS are very concerned about this. So I think what their legacy is going to be from this and how we're going to remember this incident in journalism I think is going to depend a great deal on how they handle it," she said.

CBS on Sept. 20 aired another follow-up report once the media disclosed the name of its source of the documents -- a former commander in the Texas Air National Guard, Bill Burkett, who is known within National Guard circles for trying to discredit President Bush's military service record.

Rather questioned Burkett on air about why he told CBS News the documents came from a source he later retracted. Burkett said he was pressured by CBS staff to reveal his source, so "I simply threw out a name … that was basically I guess to take a little pressure off for a moment." Full Rather interview.

After Burkett's appearance, the network said it could no longer vouch for the authenticity of the memos. Burkett did not come to CBS with the documents, rather the newscast approached him, CBS also said.

The network expressed deep regret for using the documents: "This was an error made in good faith as we tried to carry on the CBS News tradition of asking tough questions and investigating reports, but it was a mistake." Rather also offered an on-air apology, telling his audience: "I want to say personally and directly I'm sorry. This was an error made in good faith."
Full CBS statement
Rather statement

According to a CBS/Associated Press report, Mary Mapes, a veteran producer at CBS News, reported most of the National Guard story and obtained the documents. She also passed on Burkett's phone number to a top aide in the Kerry campaign, Joe Lockhart, formerly a Clinton White House spokesman.

Earlier in the year, Mapes, described by colleagues as a talented journalist with vocal liberal political beliefs, brought national attention to alleged abuses of prisoners by American soldiers in Iraq's Abu Ghraib prison by airing photos of the abuse.

Bob Zelnick, chairman of the journalism department at Boston University, told the NewsHour on Sept. 20 that the fact that Burkett later told CBS he'd gotten the documents from someone else raised questions about the news program's handling of the documents.

"That suggests to me -- unless this first person was somehow a co-conspiracy of Mr. Burkett's -- that CBS and 60 Minutes never approached this person, did not speak with them, never confirmed Mr. Burkett's story as to the origin of these documents. That's an astonishing lapse in investigative journalism," Zelnick said.

What CBS Did

Almost four months later, the panel released its report, saying the show aired a story that didn't meet CBS News' internal standards because producers wanted to be the first to break the story. But the investigation also found no evidence that politics drove the National Guard broadcast.

"The bottom line is that much of the September 8th broadcast was wrong, incomplete or unfair," Leslie Moonves, co-president of Viacom, said in a statement.

CBS senior vice president Betsy West, 60 Minutes Wednesday executive producer Josh Howard and his deputy, Mary Murphy, were asked to resign. Mapes, the producer of the story, was fired.

The panel's 224-page report listed several recommendations to prevent future failures, including the appointment of a standards and practices executive to review all investigative reporting, the use of confidential sources and authenticity of documents.

The panel also suggested that CBS News appoint a separate, independent team to investigate any news report that is challenged and foster a newsroom in which competitive pressure does not allow the broadcast of any report that is not fully vetted.

Moonves said CBS News would adopt some of the panel's recommendations and that he has already named Linda Mason, a CBS News executive who helped with the panel's investigation, to oversee and enforce newsroom standards and practices.

Two-and-a-half months after the controversial broadcast aired, Rather announced his retirement as anchor of CBS News in March 2005, 24 years after he took Walter Cronkite's place at the desk.

"I have decided it is time to move on," Rather told viewers during his Nov. 23 newscast. "It has been and remains an honor to be welcomed into your home each evening, and I thank you for the trust you've given me."

Rather made no mention of the investigation into the National Guard story, and CBS News President Andrew Heyward emphasized that the panel's findings and the announcement were "separate and apart."

Rather plans to continue as a 60 Minutes correspondent, the network said.

On May 18, 2005, CBS said it was canceling the Wednesday edition of 60 Minutes due to poor ratings and not because of the flawed National Guard report.

"This was a ratings call, not a content call," CBS Chairman Leslie Moonves told reporters.

-- Compiled for the Online NewsHour by Larisa Epatko