Joe Hagan is a contributing editor at New York Magazine, Rolling Stone, and Men's Journal

Eight years ago, Dan Rather broadcast an explosive report on the Air National Guard service of President George W. Bush. It was supposed to be the legendary newsman’s finest hour. Instead, it blew up in his face, tarnishing his career forever and casting a dark cloud of doubt and suspicion over his reporting—and that of every other journalist on the case. This month, as Rather returns with a new memoir, Joe Hagan finally gets to the bottom of the greatest untold story in modern Texas politics, with exclusive, never-before-seen details that shed fresh light on who was right, who was wrong, and what really happened.

...By all rights, [Dan] Rather, who turns 81 this year, should be enjoying a few victory laps at the close of a remarkable career. And he would be, except for one report that he will never forget, because no one will ever let him: the botched 60 Minutes segment in 2004 on George W. Bush’s Texas Air National Guard service. The report, which lasted fifteen minutes, forever damaged Rather’s reputation and ended his network TV career after forty years. Its claims were potentially explosive—that Bush had received preferential treatment to enter the National Guard in 1968 in order to avoid the Vietnam draft and that he had then shirked his duty without repercussion. As evidence, Rather produced six documents that described the alleged political pressure Bush’s commanding officer was under to “sugarcoat” possibly embarrassing moments in Bush’s record, specifically his failure to show up for a flight physical and his loss of flight status. In a presidential campaign that had become a referendum on who had the credibility to take control of the quagmire in Iraq, Rather’s report could have seriously damaged Bush’s reelection effort. But he went at the king—and he missed.

Almost as soon as the broadcast aired, a swarm of right-wing blogs assailed Rather’s documents, claiming their typeface and spacing was inconsistent with any known typewriter of the early seventies. Within days CBS was reeling as Bush allies accused Rather and his longtime producer, Mary Mapes, of using forgeries to tip a presidential election in favor of the Democrats. Twelve days after the story aired, CBS backed down, forced Rather to apologize, and established a special panel to investigate what went wrong. Forty-three days later, Bush was reelected, beating Senator John Kerry by a two-point margin in the pivotal swing state of Ohio. By the time Mapes and three other producers were ousted by CBS, the Bush National Guard story was dead and buried, with Rather’s reputation as the tombstone.

Eight years later, Bush is back in Texas, keeping a low profile and building his presidential library. Rather is still a newsman, hosting a program called Dan Rather Reports on HDNet, a niche cable and satellite channel. But he is also a man who cannot stop reliving his worst moment. This month he will publish Rather Outspoken: My Life in News, his fourth memoir but the first since his downfall. Not surprisingly, he uses the book to defend the details of his report, sharpening his ax for Bush, as well as former colleagues at CBS and its parent company at the time, Viacom, whom Rather believes caved under political pressure from the Bush White House.

“The story we reported has never been denied by George W. Bush, by anyone in his close circles, including his family,” says Rather. “They have never denied the bulwark of the story, the spine of the story, the thrust of the story.” (In fact, Bush officials have indeed denied it, repeatedly. In a conversation I had with former White House director of communications Dan Bartlett in 2007, he told me, “We believe the story is inaccurate, both the general thrust of it and the questionable sources they used.”)

Rather tried making his case in a 2007 lawsuit against his former bosses, but it was thrown out of court two years later. Nonetheless, he remains convinced that he did nothing wrong. “I believed at the time that the documents were genuine,” Rather says, “and I’ve never ceased believing that they are genuine.”...

But the CBS documents that seem destined to haunt Rather are, and have always been, a red herring. The real story, assembled here for the first time in a single narrative, featuring new witnesses and never-reported details, is far more complex than what Rather and Mapes rushed onto the air in 2004. At the time, so much rancorous political gamesmanship surrounded Bush’s military history that it was impossible to report clearly (and Rather’s flawed report effectively ended further investigations). But with Bush out of office, this is no longer a problem. I’ve been reporting this story since it first broke, and today there is more cooperation and willingness to speak on the record than ever before. The picture that emerges is remarkable. Beyond the haze of elaborately revised fictions from both the political left and the political right is a bizarre account that has remained, until now, the great untold story of modern Texas politics. For 36 years, it made its way through the swamps of state government as it led up to the collision between two powerful Texans on the national stage.

And by the time it was over, no one—not Dan Rather, not George W. Bush—would be left unbloodied....