"The job of the newspaper is to comfort the afflicted—and afflict the comfortable." So said the 19th-century journalist Finley Peter Dunne. The maxim only needs minor updating today. But in a time of the Fox News Network and pundits who are more interested in kissing up than pissing off, Helen Thomas is a throwback to the time when Edward R. Murrow, I.F. Stone and Jack Anderson were feared as purveyors of truth by the powers that be. How—and why—has it all changed? If anyone knows what makes the press tick, it is Thomas, who has covered every president and every national crisis since the Kennedy administration.

Her fourth book, Watchdogs of Democracy?: The Waning Washington Press Corps and How It Has Failed the Public, is just out from Scribner. Above all it is a political primer on how the press and the White House interact in a world where the electronic news cycle is constant. Thomas reviews how the position of presidential press secretary has evolved (F.D.R.'s Steve Early is unofficially credited with creating the job as we know it today), and there are portraits of every press secretary from Pierre Salinger to Scott McClellan. All had their strengths and their weaknesses, but Thomas has a warm spot for almost all, including Richard Nixon's beleaguered Ron Ziegler.

Over the phone one early morning, Thomas's voice is strong, direct and chipper, the laughs easy and frequent. After a few minutes it is like talking to a favorite auntie about a mutual obsession, in this case politics.

Why this book and why now? "Well," she begins, "I was outraged at the timidity of the press in the runup to the Iraqi war. I thought that they didn't ask the questions that were so relevant, especially in a couple of news conferences where it would have meant a lot. The press and Congress, of course, could have avoided this disaster, this war that has been so costly and inhumane."

The beginning of the Bush administration in 2001 was also a time of change for Thomas. After 47 years at United Press International—she joined the news syndicate during World War II and got her start in the White House by covering the presidential campaign of Sen. John F. Kennedy in 1960—she decided to resign in 2000 when Sun Myung Moon's right-wing Unification Church purchased it. Since then she has been writing a syndicated column for Hearst, which gave her the freedom to express her opinions more openly. ("I've always been a liberal," she once admitted.)

Just after taking office, President Bush dropped into the press room for a few casual handshakes with journalists. When Thomas asked him a question about the separation of church and state, Bush looked "as if I had physically struck him," Thomas writes in her book. A few hours later she was reprimanded by press secretary Ari Fleischer for "blindsiding" the president and was banished from her front-row seat, not to be called on again by the president for five years. "I don't know if he's afraid of me," she says thoughtfully, referring to Bush, "but I do ask very tough questions because I think you have one chance and you can't blow it."

Thomas has a chapter in the book entitled "Lapdogs of the Press," in which she takes her colleagues to task for their phlegmatic approach to their work. Her voice becomes harder as she says, "It isn't just the superficiality of it. They have defaulted on their roles because I honestly believe that when you retreat, going supine or spineless, at a time when they were saying in one breath for two years in the runup to the war: '9/11. Saddam Hussein. 9/11. Saddam Hussein.' Then the president finally admitted that Saddam Hussein had nothing to do with 9/11. You don't have to be a brilliant reporter to know what the Bush administration was trying to do. And the media were aiding the propaganda. Instead of saying, 'Why are you saying this? Give us the proof.' Just laying down on the job, defaulting on our role. Maybe I'm magnifying the power of the press, but I really believe that if we had put the spotlight where it should have been, we might have avoided this mayhem."

When others were silent, Thomas was vocal. In the weeks leading up to the war she assailed the hawks in both parties. She accused the Democrats of "pussyfooting around the Iraq question" and begged them to show some "backbone." As Bush built his case for removing Saddam in his State of the Union address she remained skeptical. "The president blew it," she wrote, "he passed up a chance to make a convincing case for why the United States should attack Iraq." She points to Bush's press conference of March 6, 2003—just 12 days before the war started: "It was very clear the president was telling us he was going to war, and everybody sort of softened the blows and the questions were just off the point. They should have said, 'why, explain why.'"

Thomas was recently introduced to a whole new TV generation when she appeared in Stephen Colbert's infamous video that was shown at the White House Correspondents' Dinner. In the video, Colbert is supposedly applying for the job as the president's press secretary and is hounded and chased by Thomas around the White House grounds. Colbert's act was panned by the press corps, but given alleluias by the bloggers. Thomas' opinion? "I thought he was terrific, but of course I don't think the president and Mrs. Bush liked it." She also thinks she knows why the mainstream media—also skewered by Colbert in his skit—gave the Comedy Central's star a thumbs down: "Well, I guess they might have thought it was too edgy or disrespectful." She then laughs as she gets to the crux of the matter. "I don't think we like to take it, either. Who needs that?"

Thomas has covered nine presidents, and it appears her first is still her favorite. In the book she calls John F. Kennedy "the most inspired leader of the last half of the twentieth century." That doesn't stop her from criticizing J.F.K. for instituting secrecy as a way of shielding bad policy, which every president since has embraced. But criticisms aside, Thomas saw in Kennedy an optimism about America and the world that is sorely lacking in public life today: "When he took the presidency, he knew a whole new world was opening up for America, that he should lead. He signed the first nuclear test ban treaty. He said we're going to land men on the moon in a decade. He didn't live to see it, but we did it. He told young people to go into public service, that it could be the crown of their careers. He gave us a sense of uplift and also hope, and I think we haven't had that since. Inspiration."

Helen Thomas will be 86 in August and she has no intention of retiring. "No. I may be forced to, you never know from day to day. I never had that kind of security in all my life. I love my work and you do it as long as you can, are able to, and I sure would like to keep going." In her book she writes: "I had the honor of closing one of Kennedy's news conferences with a 'Thank you, Mr. President.' And I recall his memorable 'saved by the bell' look when he responded with relief, 'Thank you, Helen.'" After 60 years on the job, this watchdog of democracy has earned another "Thank you" for, at the least, afflicting the all too comfortable.