"I will resign repeat resign and I mean it repeat mean it."

Dexter Filkins writes about the effect that David Halberstam, along with Malcom Browne and Neil Sheehan, had on the coverage of the war in Vietnam. Their skepticism and reporting on the reality on the ground versus the government's happy talk helped end the war and, ultimately, the Nixon administration. And inspired reporters covering Iraq these past four years.

Mr. Halberstam, then working for The New York Times, went on to demonstrate through a series of forceful dispatches that the chaotic reality unfolding on the ground in Vietnam bore little resemblance to the upbeat accounts offered by American presidents and generals who were prosecuting the war. Journalism and, more broadly, the relationship between the American people and their elected servants in Washington, was never the same again. Mr. Halberstam, who died Monday in a car accident, set a standard for skepticism of official war-time pronouncements that carries on to this day.

During four years of war in Iraq, American reporters on the ground in Baghdad have often found themselves coming under criticism remarkably similar to that which Mr. Halberstam endured: those journalists in Baghdad, so said the Bush administration and its supporters, only reported the bad news. They were dupes of the insurgents. They were cowardly and unpatriotic. Indeed, reporters who filed dispatches pointing out the pitfalls experienced by American troops sometimes found it difficult to secure an embed with an American military unit. Other reporters — including this one — were sometimes excluded from official briefings inside the Green Zone.

“Frankly, part of our problem is a lot of the press are afraid to travel very much, so they sit in Baghdad and they publish rumors,” Paul D. Wolfowitz, then the deputy secretary of defense, said in 2004.

Mr. Halberstam and his colleagues in Vietnam, like Neil Sheehan of United Press International and Malcolm W. Browne of The Associated Press, both later of The Times, had it a lot tougher than reporters in Iraq do today, if only because they were the first. Few journalists with major American newspapers or television networks had dared to publicly question the veracity of America’s military leaders — or an American president — in wartime, least of all a 29-year-old reporter not that long out of college.

By his own account, Mr. Halberstam had gone to Vietnam a believer in the American project, but found himself increasingly disillusioned by events he was witnessing up close. The public representations made by American leaders — of numbers of Vietcong killed, of South Vietnamese soldiers trained — seemed so at odds with what Mr. Halberstam and the other reporters were seeing that they came to regard the official briefings as little more than acts of comedy.

That skepticism, in the American press, was new. “The press at the time, and by that I mean the editors, were living in the shadow of World War II,” Mr. Sheehan said in an interview. “The senior military and the senior diplomats had enormous credibility with the news media. If General Patton gave you a briefing on what he was going to do to the Germans — and he always brought the press with him, because he thought it was important — you could expect a pretty straightforward account.”

Mr. Halberstam, an intense, sometimes intimidating man, came into direct conflict with President Kennedy — who pressed to have him pulled from Saigon — and with his own editors at The Times, who sometimes questioned the divergence between his and the official accounts.

In one incident, recounted in Mr. Sheehan’s book, “A Bright Shining Lie,” Mr. Halberstam exploded at his editors in New York, who had asked him about an article filed by a competitor that more closely tracked the official version. “If you mention that woman’s name to me one more time I will resign repeat resign and I mean it repeat mean it,” Mr. Halberstam wrote in a cable.

In another incident in 1963, Mr. Halberstam filed an article about a series of arrests staged by the Saigon government that was flatly contradicted by the State Department in Washington. After much debate, editors at The Times decided to run two articles on its front page — one from Washington, based on the State Department’s version, and the other from Mr. Halberstam. “Three days later,” Mr. Sheehan wrote, “other events forced the State Department to admit that the official version had been wrong.”

Similar clashes between the Bush administration and the press have unfolded during the war in Iraq, particularly in its early phases. In late 2003 and early 2004, as security around Iraq was deteriorating, reporters in Iraq were sometimes mystified by the rosy briefings they were given inside the Green Zone. In the streets where they lived and worked, they witnessed car bombings and assassinations, while the spokesmen for the Bush administration talked mostly about smiling Iraqis and freshly painted schools.

“There were two realities — one inside the Green Zone, and the reality every day, talking to people in the street,” said Anthony Shadid, a Washington Post correspondent whose Iraq dispatches won a Pulitzer Prize in 2004. “They never did intersect.”