Mark Thompson, a defense reporter for Knight-Ridder Newspapers, was not involved with a false news report in the San Jose Mercury News, part of the Knight-Ridder chain,that Iraq had suffered 150,000 military casualties. The report, cited in a Post story yesterday, was written by a Mercury News reporter. (RP 1/29/91)

Twenty-four hours after U.S. and allied warplanes attacked Baghdad, the San Jose Mercury-News declared in a front-page headline: "Iraqi troop loss is put at 150,000." That casualty figure was far higher than the toll when the atomic bomb was dropped on Hiroshima.

The erroneous report, and a Cable News Network description of the "decimated" state of Iraq's elite Republican Guard, were among a spate of enthusiastically upbeat media accounts in the first days of the Persian Gulf War that contributed to what Defense Secretary Richard B. Cheney yesterday called the country's "initial euphoria" about the conflict. Perhaps inevitably, such reports have led to a second wave of reassessment in which progress is described as far more ambiguous than was first suggested by videotapes of American bombs destroying Iraqi buildings with pinpoint accuracy.

This reassessment produced the unusual spectacle of a Defense Department chief cautioning reporters at a news conference that the war may not be going as well as they had written and broadcast. Indeed, he said, modern warfare cannot be neatly assessed and packaged in 24-hour news cycles to meet the voracious demands of newspapers and television.

"A military operation of this intensity and complexity cannot be scored every evening like a college track meet or a basketball tournament," Cheney said.

At another point, Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, told reporters: "Trust me. Trust me."

But many news executives remain skeptical of the Pentagon, saying the military helped to fuel the initial optimism and continues to distort the coverage by releasing little hard information about the effectiveness of the allied air assault.

Robert Ingle, executive editor of the Mercury-News, said military officials "were creating an image in which everything was going spectacularly well" to "make themselves look good . . . . In hindsight, common sense says, that's not the way war goes at all." The erroneous article about the 150,000 Iraqi military casualties, he said, was based on "an intelligence report we got from a Pentagon source."

Mark Thompson, defense correspondent for Knight-Ridder Newspapers, which includes the Mercury-News, said the Pentagon's selective release of videotapes showing successful U.S. bombing raids had a more dramatic impact than anything reporters wrote or said.

"I think that colored the press and the public's perception of how swimmingly things were going," he said. "Reporters went, 'Wow! Shebang! This is great!' I'd like to see some bombs not destroying buildings with a single bound."

Some Pentagon officials say misunderstandings between journalists and war commanders were inevitable. One official said yesterday's briefing was meant to combat "this minor credibility gap that's developing."

"I think there's ample blame to go around for both sides," said the official, a senior officer who often provides guidance to reporters. "The military is totally inept in the way it approaches press relations. It's obvious that these briefers have no idea what the reporters are looking for, and they're also scared to death."

In the Pentagon's view, wartime brings hundreds of novice military reporters, many asking what officers regard as naive or inappropriate questions -- for example, inquiries about future military operations that cannot be answered without jeopardizing the safety of U.S. troops. Some officers have used the term "nit-witness news" to describe the questions at recent Pentagon briefings.

One thing clear to both sides is that, in a war in which every military briefing in Saudi Arabia or Iraqi missile attack on Israel produces live updates on Cable News Network, the rules have changed forever. Some analysts question whether World War II could have been conducted so successfully had the public been subjected to televised casualty reports every few hours.

Timothy Russert, NBC's Washington bureau chief, said Iraqi President Saddam Hussein "is being very aggressive in his propaganda campaign, and we recognize that. Yet it is his version of the war {being presented} so far. The Pentagon has been reluctant to put out their version."

In the absence of hard information from the U.S. side, Russert said, "We are probably overplaying the Scud attacks and the POWs and the lost American aircraft . . . . You can't make critical judgments in a vacuum."

Pentagon officials insist that no one with access to intelligence data could have told reporters that Iraq's elite Republican Guard had been "decimated" or the Iraqi air force destroyed, as broadcast reports claimed, said one official who spent the first hours of combat in a Pentagon operations center. "It was way too early for anyone to know that," he said.

Barbara Cohen, CBS's Washington bureau chief, said the media and the military "were feeding off each other" during that initial combat. "They had a tremendous need to report success, and we had a need to come up with a headline," she said. "Everyone was in love with the smart bombs and the Patriots."

A classic misunderstanding arose from the Pentagon's initial claim that 80 percent of its combat sorties had been "effective." Many reporters and television viewers apparently thought that meant that 80 percent of the targets had been destroyed, and some reporters say officials deliberately fostered that impression.

But Pentagon spokesmen say they carefully explained that an effective mission means only that the pilot identified his target, dropped a bomb and returned to base. The extent of damage cannot be determined without further analysis, they said.

Terry Eastland, a fellow with the Ethics and Public Policy Center, said some of the early "hype" could be explained by "jingoism" and "patriotic fervor" among reporters.

"In the opening hours, you experience the adrenaline," said Knight-Ridder's Thompson. "There seemed to be a silent chant of 'Okay, let's go!' {Reporters} are sort of rooting for the home team."