Alex Brandon / AP Former Vice President Dick Cheney addresses the Conservative Political Action Conference in Washington, February 10, 2011.

Early critics have argued that Dick Cheney’s forthcoming memoir, held under strict embargo until its official release on Aug. 30, is a predictable reprise of old arguments. Like most examples of the genre, In My Time has plenty of those. But a careful reading of Cheney’s narrative, obtained by TIME, turns up quite a bit of new material. Sometimes subtly and sometimes starkly, the vice president’s story takes issue with the public record on pivotal events.

One of Cheney’s most surprising claims involves the Bush administration’s internal crisis over domestic surveillance by the National Security Agency. That episode, which came to a head in a 2004 hospital visit by White House aides to a gravely ill Attorney General John Ashcroft, was among the most dramatic in Bush’s two terms. It was notable, if not unique, in presidential history because subordinates forced the commander-in-chief to reverse a high-stakes order in wartime. In Bush’s memoir, he wrote that he had to back down (“accommodate the Justice Department’s concern,” as he put it) or watch “my administration implode” in “the largest mass resignation in modern presidential history.” My book on Cheney quotes Bush’s lieutenants, including communications director Dan Bartlett, as comparing the event to Watergate and describing it as a turning point in the Bush-Cheney partnership.

At issue was a closely held secret: that Cheney had devised, and Bush approved, an NSA operation to monitor the phone calls and emails of U.S. citizens without a warrant, part of which later became known as the Terrorist Surveillance Program. After more than two years of going along with “the vice president’s special program,” the Justice Department concluded that parts of it were illegal. Deputy Attorney General James B. Comey later told Congress, and authoritative sources confirmed privately last week, that Ashcroft decided on March 4, 2004 to stop certifying the surveillance as lawful unless the White House scaled it back. That same afternoon, Ashcroft fell ill with a nearly lethal case of pancreatitis.

(PHOTOS: Cheney’s Rise)

A week-long standoff ensued. Comey, as acting attorney general, refused to reauthorize the program, which was set to expire. On March 10, Bush sent White House Counsel Alberto Gonzales and Chief of Staff Andrew Card to obtain Ashcroft’s signature as he lay in intensive care. When Ashcroft refused, Cheney’s lawyer drafted and Bush signed an order renewing the warrantless surveillance over explicit Justice Department objections.

Cheney’s version of this story adds a stunning twist: Ashcroft told Bush on the phone, before Gonzales and Card arrived, “that he would sign the documents” to certify the surveillance as lawful. But the two men found Comey there when they arrived, Cheney writes, and “it became immediately clear that Ashcroft had changed his mind.” Only then, Cheney suggests, did the White House aides learn that Ashcroft “had delegated all the responsibilities of his office to the Deputy Attorney General.”

The former vice president’s account is meant to rebut the consensus view at Justice and the FBI that Bush tried to circumvent Comey’s lawful authority and take advantage of a sick man. But it is very difficult to see how Cheney’s claims on either point could be true.

Comey and four other officials with contemporary knowledge told me in interviews that Janet Ashcroft, the attorney general’s wife, refused two attempts that evening by the White House operator to patch a call to her husband. Doctors said he was far too sick to speak. According to contemporary notes from Ashcroft’s FBI security detail, quoted in an inspectors general report of 2009, she refused to put her husband on the phone even when Bush joined Card on the line. “Mrs. Ashcroft took the call from Card and the President and was informed that Gonzales and Card were coming to the hospital to see Ashcroft regarding a matter involving national security.” Bush implied in his memoir that he did reach Ashcroft, but said he told him only that “I was sending Andy and Al to talk to him about an urgent matter.”

(LIST: 10 Bush Figures We’ll Miss)

Even if Ashcroft picked up the phone, there are many reasons to doubt Cheney’s version of the call. It would mean that Bush discussed a codeword-classified intelligence program on an open phone line; that Ashcroft took exactly the opposite position that he took before and after the call; and that the attorney general was even coherent. Those around Ashcroft that evening say he was heavily doped on morphine, slipping in and out of awareness. “I found him barely conscious,” Comey said in an interview. “I had trouble getting him focused, oriented as to time and place.” Mueller wrote in contemporary notes that Ashcroft was “feeble, barely articulate.”

Even harder to credit is Cheney’s suggestion that the White House did not know until that moment that Comey had assumed Ashcroft’s powers. David Ayres, Ashcroft’s chief of staff, called deputy White House chief of staff Joe Hagin from the emergency room a full week earlier, on March 4, to say the attorney general was incapacitated. The next day, Justice sent formal notice to Gonzales’s deputy, David Leitch, that Comey had taken the reins. On March 6, newspapers and broadcast networks carried variations of this report from CNN: “Deputy Attorney General James Comey is acting as attorney general while Ashcroft is hospitalized.” For the next four days, Comey repeatedly filled in for Ashcroft in White House meetings. In one of them, Bush asked after Ashcroft’s health and Comey replied, “Not well.”

(UPDATE: David Leitch emails to deny that he received written or verbal notice from Ayres on March 5, 2004 that Comey had taken over from Ashcroft. “I cannot speak to and wouldn’t claim to be aware of each and every transmission that DOJ may or may not have had with the White House on the subject,” he wrote, adding: “Of course, like everyone else, I knew that the AG was in the hospital, but not every hospital stay by a cabinet member results in a transfer of authority, even when accompanied by press reports to that effect, and I was unaware on the date of the hospital visit that Comey was formally acting as AG.” Gonzales, on the other hand, appeared to confirm in Senate testimony in 2007 that he was well aware of the transfer. Sen. Arlen Specter said to Gonzales: “He had already given up his authority as attorney general.” Gonzales replied, “And he could always reclaim it. There are no rules about [EM] ” Specter cut him off: “While he was in the hospital under sedation?”)

Cheney misstates another crucial point, alleging that it was not until “the spring” of 2004 that Justice began “raising concerns” about the surveillance program. In fact, the chief of the Office of Legal Counsel, Jack Goldsmith, started expressing strong doubts in December 2003, and Comey joined him in January. David Addington, Cheney’s general counsel, engaged in a ferocious effort over the next three months to suppress a growing legal rebellion. When lawyers from the NSA asked to see the opinions under dispute, Addington angrily refused and told them to back off.

(PHOTOS: A Farewell to the Bush Presidency)

It is very likely true, on the other hand, that Bush was unaware of the crisis until the last moment. My reporting supports the president’s published account that he did not know about the Justice Department’s objections until the day before the program was set to expire. The sudden news, portrayed by Card and Cheney as a sudden turnabout by Comey, is what prompted Bush to dispatch his aides to the hospital. Even then, it was not until the next morning – when he discovered that Comey and FBI Director Robert Mueller were about to resign – that Bush understood his presidency was at risk.

Cheney’s biggest contributions to the history of this episode are his matter of fact acknowledgment that the surveillance program was his initiative, that Addington drafted and held the only copy of its crucial documents, and that he disagreed with Bush’s decision to give in to “threats of resignation.” Cheney urged Bush to stand his ground, and he clearly implies that the president lost his nerve.

Bush tells it differently. “I had to make a big decision, and fast,” he wrote in his memoir. “Some in the White House believed I should stand on my powers under Article II of the Constitution and suffer the walkout…. I was willing to defend the powers of the presidency under Article II. But not at any cost. I thought about the Saturday Night Massacre in October 1973, when President Richard Nixon’s firing of Watergate prosecutor Archibald Cox led his attorney general and deputy attorney general to resign. That was not a historical crisis I was eager to replicate.”

The Bush-Cheney relationship never fully recovered from that day. Bush wrote, without naming Cheney, that he “made clear to my advisers that I never wanted to be blindsided like that again.” March 11, 2004 was the day the president of the United States discovered that the vice president’s zeal could lead him off a cliff. Cheney confirms throughout his memoir that he holds only contempt for office-holders who place politics over principle. The nation’s second-highest elected official was, paradoxically, an anti-politician. A president cannot afford to be. Here and throughout, Cheney’s memoir is a telling account – occasionally explicit, more often implied — of their mutual disillusionment.

Barton Gellman, a Time contributing editor-at-large, is author of Angler: The Cheney Vice Presidency (Penguin Press, 2008).