Former CBS anchor Dan Rather told a Raleigh radio interviewer Tuesday that he stands by the discredited "60 Minutes Wednesday" report that President Bush received preferential treatment when he joined the Texas Air National Guard and failed to meet requirements while enlisted.

In a testy interview on WPTF-AM, Rather also vouched for the authenticity of documents used in the report, which bloggers and the national media challenged immediately after the story aired in September 2004.

"I believe them to be real," Rather told interviewer Donna Martinez. "I wouldn't have put them on the air if I hadn't." Later in the interview he said: "To this day, nobody has ever proven that the documents were not what they purported to be."

The election day interview, which WPTF (680 AM) will rebroadcast Wednesday between 6 and 8 a.m., was tied to the launch of "Dan Rather Reports," an investigative news series on HDNet, a digital-tier cable channel owned by Dallas Mavericks owner Mark Cuban. It premieres Nov. 14, right at the two-year anniversary of Rather's decision to vacate the CBS anchor desk in the wake of the Bush story, which CBS retracted.

Four producers and executives were subsequently fired, and Rather himself apologized, saying he no longer had "the confidence in these documents that would allow us to continue vouching for them journalistically."

On Tuesday, though, he insisted that the story was true.

"What happened to us is, a lot of people … didn't like the fact that we reported the story of what President Bush's time in the National Guard was, and wasn't," he said. He called the CBS-commissioned review of the network's handling of the story as "an independent investigation headed by a good friend of President Bush, and a political ally of President Bush's." He was referring to Associated Press CEO Louis Boccardi and former U.S Attorney General Richard Thornburgh, who had served in the administrations of presidents Reagan and Bush Sr.

Martinez countered by reading from a 2005 cbsnews.com report on the panel's findings, which concluded that the story "was neither fair nor accurate and did not meet the organization's internal standards."

That's when the interview got tense.

"Well, obviously, you have a political agenda this morning," Rather said.

Speaking by phone after the broadcast, Martinez, who works for the conservative John Locke Foundation in Raleigh, denied that her questions were politically motivated.

"Obviously this is a very serious story that was of national importance and had the potential to sway a presidential election," Martinez said.