Former White House spokesman Scott McClellan leaves no doubt that an on-bended-knee press corps made it easier to peddle propaganda about the war in Iraq.

“If anything, the national press corps was probably too deferential to the White House and to the administration in regard to the most important decision facing the nation during my years in Washington, the choice over whether to go to war in Iraq,” he writes in his new memoir, What Happened: Inside the Bush White House and Washington’s Culture of Deception (Public Affairs)

“The collapse of the administration’s rationales for war, which became apparent months after our invasion, should never have come as such a surprise,” McClellan explains. “In this case, the ‘liberal media’ didn’t live up to its reputation. If it had, the country would have been better served.”

There is no mystery as to why the White House might want the press corps to swallow spin.

But why did the reporters do it?

“The press corps was under enormous pressure from corporate executives, frankly, to make sure that this was a war presented in a way that was consistent with the patriotic fever in the nation and the president’s high approval ratings,” says CNN’s Jessica Yellin, who was an MSNBC reporter during the run-up to war and then worked for ABC from the summer of 2003 until the summer of 2007.

Yellin told CNN, “(My) own experience at the White House was that the higher the president’s approval ratings, the more pressure I had from news executives–and I was not at this network at the time–but the more pressure I had from news executives to put on positive stories about the president…”

CNN host Anderson Cooper seemed shocked, asking, “You had pressure from news executives to put on positive stories about the president?”

“They wouldn’t say it in that way, but they would edit my pieces,” explained Yellin. “They would push me in different directions. They would turn down stories that were more critical, and try to put on pieces that were more positive. Yes, that was my experience.”

While many current members of the White House press corps are circling the wagons and defending what is left of their credibility — NBC’s David Gregory, who often tangled with McClellan, says, “I think my work speaks for itself and is the clearest refutation of Scott’s claim”–a few like Yellin are acknowledging the reality that is now laid bare.

Perhaps the bluntest assessment by an insider of the media’s missteps came from CBS Evening News anchor Katie Couric, who said she thought McClellan was “fairly accurate” in his description of a “too deferential” press corps.

“I do think we were remiss in not asking some of the right questions. There was a lot pressure from the Bush White House,” said Couric, who worked for NBC when the war was approaching. “I remember doing an interview and the press secretary called our executive producer and said, ‘We didn’t like the tone of that interview.’ And we said, “Well, tough. We had to ask some of these questions.” They said, ‘Well, if you keep it up, we’re going to block access to you during the war.’ I mean, those kind of strong-arm tactics were … really inappropriate.”

Phil Donahue agrees.

Though he is best known as the pioneer of daytime talk television, Donahue was hosting an evening talk show on MSNBC as the war approached. That show was canceled when NBC executives decided they did not want to air dissenting voices– even if the dissenters happened to be right. “The board members of the large megamedia companies, while America is waving the flag and supporting the president, do not want their cable or television channels to be occupied by dissent, protest, all the rights that have been fought for and died for in past wars,” says Donahue.

Of his former MSNBC/NBC colleagues, Donahue says, “Both Katie and Jessica are absolutely correct. It is a shame that we don’t have this kind of commentary from more of the male anchors who were at the center of the coverage in October 2002.”