Which is why the two-front media war being fought this week over two conflicts separated by almost 40 years, the Korean War and the Gulf War, is so extraordinary.

First, U.S. News & World Report and the online edition of the military newspaper Stars and Stripes published long, well-documented articles calling into serious question an
Associated Press account of an alleged US massacre of hundreds of Korean civilians in July 1950. The AP story -- published last September 29 on the front page of nearly every major newspaper -- was recently honored with a Pulitzer Prize for investigative reporting. (The results of an official inquiry, begun in the wake of the AP story, are scheduled to be announced later this year.)

Then, the New Yorker ran a much-anticipated 25,000-word article by Seymour Hersh -- who won a Pulitzer for exposing the My Lai massacre in Vietnam a generation ago -- charging that retired Army general Barry McCaffrey may have committed "war crimes" during the 1991 Gulf War. Hersh's most serious accusation: that McCaffrey, itching for battle, may have deliberately moved his troops well beyond the official cease-fire line and slaughtered hundreds of retreating Iraqi soldiers. Hersh's article couldn't have come at a worse time for McCaffrey, who is now the White House drug czar and the chief advocate for the administration's plan to send military advisers and materiel to Colombia.

Neither the AP's critics nor Hersh have definitively proven their case. On Monday, the AP released a lengthy statement that supports its original reporting. McCaffrey, who has been denouncing Hersh for the past month, points out that the Army investigated and cleared him of the very charges that Hersh levels. In other words, barring some blockbuster revelation, we're a long way from the AP's having to turn in its latest Pulitzer, or, for that matter, from Hersh's winning another one.

Nevertheless, the two controversies are fascinating for what they say about the uneasy relationship between journalism and war. Both incidents took place out of the media's view. The Korean incident occurred in the context of an emergency invasion to stop North Korean troops. In Iraq, media witnesses were kept at bay by strict censorship rules that the Vietnam-scarred military brass had succeeded in imposing. Thus, long after the fact, the AP and Hersh tried to bring order and logic out of the chaos and terror of war. It can be done, and of course Hersh himself, in his exposé of the My Lai massacre, submitted the prime example.

In general, though, imperfect memories of terrifying moments that took place nine (in Hersh's case) and 50 (in the AP's case) years ago, even when some new light is shed on poorly understood events, are not a dependable path to the truth. Witness the Boston Globe's usually scrupulous David Warsh. In a 1996 column published in the heat of Senator John Kerry's tough re-election battle with then-governor Bill Weld, Warsh wrote a column, based largely on an ambiguous comment from Tom Belodeau, who had served with Kerry in Vietnam, asserting that Kerry may have shot a wounded, unarmed North Vietnamese soldier -- "a practice not uncommon in those days," Warsh wrote, "but a war crime nevertheless." At a news conference Kerry called to denounce Warsh's characterization, an outraged Belodeau said of the killed soldier, "This man was not lying on the ground. He was more than capable of destroying that boat and everybody on it. Senator Kerry did not give him that opportunity. For that reason, myself and three other people are here today." (See "Don't Quote Me," News, November 1, 1996.)

Or witness perhaps the best-known example of all: the fiasco over CNN and Time magazine's 1998 Tailwind story, which stated that US forces in the Vietnam War had tracked down American deserters accompanying North Vietnamese troops and attacked them with nerve gas. Within days, one of the two principal sources had denied ever having confirmed the use of nerve gas, and the other had been discredited. The story had to be retracted, and CNN issued an abject public apology.

The Hersh-McCaffrey battle is still in its early stages; Hersh's story has yet to come under the same sort of outside scrutiny as the AP's reporting. Indeed, Hersh's article is so detailed and daunting that it may take a dogged investigator as many months to review it as it did Hersh to research it in the first place.

The boundaries of the dispute over the AP story, on the other hand, are now pretty well established. Indeed, it already seems clear that the AP undermined its own exhaustive reporting by relying too heavily on quotes from veterans who may have been lying, or just plain confused, as to whether they even witnessed the events they purport to describe.

According to the Associated Press report (available at www.ap.org), several hundred South Korean refugees, including women and children, were executed by machine-gun fire over a three-day period in July 1950 beneath a bridge in the village of No Gun Ri. The alleged incident took place in the first panicked weeks of the Korean War, when US troops -- "young, green and scared," as the AP put it -- were rushed into battle to stop a headlong invasion by North Korean troops.

It has long been known that something terrible happened at No Gun Ri; survivors have been pushing compensation claims for many years. What was new, and startling, about the AP story was the allegation that a planned slaughter took place systematically, over three days; that an officer or officers at the scene may have given orders to conduct the slaughter; and that American commanders had given orders, in writing and in apparent contravention of international law, to treat civilians as possible enemy agents and to prevent them from leaving the area. If proven, the AP noted, the No Gun Ri incident would parallel the slaughter at My Lai in 1968, in which more than 500 Vietnamese civilians were killed by US forces.

The AP relied heavily on two alleged participants: Edward Daily and Eugene Hesselman. Daily, who claimed to have been a machine-gunner at No Gun Ri, provided the most evocative quotes, including this: "On summer nights, when the breeze is blowing, I can still hear their cries, the little kids screaming." In a follow-up piece on NBC's Dateline, Daily added that he had received a direct order to kill the refugees.

Hesselman told the AP that Captain Melbourne Chandler, after speaking with his superiors by radio, ordered his men to fire. "Chandler said, `The hell with all those people. Let's get rid of them,' " Hesselman told the AP.

The AP's use of Daily and Hesselman may turn out to have been ill-advised. In similar pieces, U.S. News and the Web site of the Stars and Stripes (www.stripes.com) offered considerable documentary evidence suggesting that neither Daily nor Hesselman was anywhere near No Gun Ri. Daily is portrayed as boastful and disturbed, a man long eyed with suspicion by fellow veterans. "I take three strong pills for mental illness," Daily told U.S. News. Hesselman, U.S. News says, was almost certainly evacuated with an injury before the incident took place. Other veterans interviewed by U.S. News complained that the AP distorted their quotes and took them out of context. And another veteran, Norman Tinkler, told U.S. News that he did shoot civilians, killing a number of innocent people in one short burst of machine-gun fire. But in a comment that speaks to the horror and confusion of war, Tinkler insisted that no one ordered him to fire: "Refugees came through our positions the day before and pulled pins and threw three hand grenades at our guys. I wasn't going to let them get near me. . . . And yes, I fired at them. Nobody gave me orders. Nobody was there to give me orders."

In defense of its reporting, the AP issued a lengthy statement on Monday attempting to show that Daily, Hesselman, and Delos Flint, a third alleged participant who U.S. News had reported may not have been on the scene, were in fact at No Gun Ri at the time of the alleged massacre, and that U.S. News had relied too heavily on military records of dubious accuracy. The AP further reported that Daily's therapist believed his mental illness stemmed from his involvement in slaughtering civilians. And it sought to demonstrate -- with some success -- that the so-called out-of-context quotes were not taken out of context at all.

"Our story, published almost eight months ago, was careful to reflect the contradictions, ambiguities, and scarred memories that marked our attempts to reconstruct an event from 50 years ago," AP executive editor Jonathan Wolman was quoted as saying.

Clearly it's crucial for the AP that its reliance on Edward Daily and Eugene Hesselman hold up to scrutiny. In the CNN/Time Tailwind report, producer April Oliver -- the lead reporter -- leaned heavily on platoon leader Robert Van Buskirk's assertion that he had witnessed a nerve-gas-like compound being dropped on North Vietnamese and Pathet Lao troops during an incursion into Laos, and that the US forces' mission included tracking down and killing American deserters. In one case, he said, he had personally tossed a grenade down a hole where he had seen a white soldier disappear. CNN and Time also reported that then-admiral Thomas Moorer had "confirmed the use of sarin," a type of nerve gas, in the Laotian operation.

The Tailwind report fell apart when Moorer, who was 87 at the time he was interviewed, said he couldn't accurately remember the 28-year-old events, and that he had not confirmed the use of sarin (CNN later paid him a six-figure settlement). Worse, Van Buskirk was discovered to have co-written a 1983 book about his exploits in Southeast Asia, yet had somehow failed to mention the use of nerve gas at that time, casting considerable doubt on the credibility of his comments to CNN; he also was found to be suffering from serious mental problems. Oliver and her supervisor, Jack Smith, were fired, and foreign correspondent Peter Arnett, who had lent his face to the CNN report and his byline to the Time article, was allowed to keep his job only after making the humiliating admission that he had actually contributed "not one comma" to the entire project.

To this day, Oliver and Smith insist that their report was accurate, and that Moorer's and Van Buskirk's contributions weren't really that important. The problem is that no matter how much other reporting Oliver may have done, Moorer and Van Buskirk were who she and her colleagues used to tell the story. As a lawyer might tell a jury, if there's something rotten at the top of the barrel, you're under no obligation to fish around underneath.

Likewise, although the Associated Press cites interviews with some 50 sources and documentary evidence to back up its No Gun Ri story, it's going to have a damn time hard defending its findings if it can be proven that its most eloquent witnesses weren't even there.

Seymour Hersh isn't April Oliver, or even a grizzled wire-service veteran. He is, rather, one of the most admired journalists of our time, not just for his My Lai exposé, written when he was working for the New York Times, but for his withering 1983 biography of Henry Kissinger, The Price of Power. Hersh's reputation, though, has declined in recent years. His 1997 book on John F. Kennedy, The Dark Side of Camelot, was not well received, and it didn't help when it was learned he'd nearly been snookered by a con artist offering him bogus Marilyn Monroe diaries. Thus, if Hersh's exhaustive New Yorker piece on General Barry McCaffrey, titled "Overwhelming Force," is the work of a master, it is also the work of a man with something to prove.

One advantage of a 25,000-word article is that the reader gets to see not just the headline stuff, but the supporting material as well. Hersh presents voluminous details, with long, on-the-record quotes, to back up his assertion that McCaffrey went to deadly lengths in order to burnish his battlefield résumé. Hersh examines several incidents, the most telling of which is the Battle of Rumaila. According to Hersh, McCaffrey -- flouting orders -- moved his troops past the cease-fire line so that they were within firing range of a causeway, a narrow route in Iraq's soggy south through which thousands of Iraqi troops were retreating after their defeat and expulsion from Kuwait. Then, on March 2, 1991, acting on little more than a suspicion, or a hope, that the Americans had been fired upon, McCaffrey turned loose the full power of his forces, destroying Iraqi tanks and soldiers indiscriminately -- in essence, slaughtering hundreds of men who had already surrendered and were heading home. "There was no need to be shooting at anybody. They couldn't surrender fast enough. The war was over," Hersh quoted Lieutenant General James Johnson as saying.

As McCaffrey has noted, he was indeed investigated and cleared. However, Hersh presents considerable evidence that some of the investigators, and even McCaffrey's superiors, were intensely uncomfortable with his actions in Iraq. The charges were not pursued because no one could prove that Iraqi forces hadn't fired first. But Hersh contends that many Army officials, including McCaffrey's superiors, continued to regard McCaffrey's conduct as inexcusable. Besides, as Hersh quotes "a retired major general" as saying, "They'd just won a war and didn't want to shit in their mess kit."

McCaffrey's defense is simple and direct. He says that his men were indeed under Iraqi attack, that he acted appropriately, and that investigators had cleared him. "This is nonsense, this is revisionist history," McCaffrey said of Hersh's piece in an appearance on the Today show. He accused Hersh of "recycling charges that were investigated 10 years ago. It conclusively demonstrated that there was no wrongdoing." McCaffrey also charged Hersh with acting out of personal animus, which Hersh has denied.

The only thing that seems certain is that either Hersh or McCaffrey will come out of this with his reputation in tatters.

In a sense, the charges and countercharges regarding the Associated Press's investigation into No Gun Ri and Seymour Hersh's article on Barry McCaffrey are part of the ugly legacy of Vietnam. Those of us who lived through the nightly body counts and the assurances that victory was just around the corner, while American troops were ordered to destroy a country for no reason, are quick to believe accusations of wrongdoing, dismissive of official denials. No Gun Ri may have taken place long before Vietnam, but now it is being viewed through the filter of that terrible time.

As Daniel Schorr said in an NPR commentary on Monday, we can't take McCaffrey's defense at face value because the military establishment has lied to us for too many years about too many things. Such skepticism is, unfortunately, an essential cultural survival skill, especially given that a man who may have indiscriminately killed retreating Iraqis now wants to drag us into the jungles of Colombia to fight his phony drug war.

Ultimately, it may be impossible to reconstruct such long-past events, and it may, in some ways, even be unfair: conduct that may be justified under conditions of panic and terror can look grotesque when considered coolly and unemotionally, years after the fact. Nevertheless, digging out the truth is important for its own sake, and for the sake of our national conscience. James Manchester, a former Army officer who ran afoul of McCaffrey, put it this way in an interview with Hersh: "There have to be limits, even in war. Otherwise, the whole system breaks down."

Despite the efforts of the AP and of Hersh, it's not clear whether the system broke down at No Gun Ri or in Iraq. It seems like a cliché to suggest that more investigation is needed. But, yes -- more investigation is needed.