RIGHT AFTER dedicated doctors but before crusading coroners, journalists have recently come to occupy the spot of "most heroic profession." Walter Cronkhite, Wood ward & Bernstein, Lou Grant; in the public eye there is often a suspicion that underneath those Lois Lane outfits and Clark Kent glasses lurks the big red S, out to correct the injustices of the world with the blinding light of truth.

But when the blinding light of truth is turned back on the media, they appear in more human proportions. More often witnesses than participants, Roland Joffe's The Killing Fields shows that journalists can be just as easily trapped in the flow of history as the persons they write and report about.

The Killing Fields recounts the true story of American reporter Sydney Schanberg and his Cambodian assistant Dith Pran. During the early 1970s American bombers poured several thousand tons of TNT onto Cambodia, resulting, quite logically, in the death of several thousand innocent Cambodians. Schanberg covered these American atrocities for the New York Times, with Pran working overtime as photographer-translator-copy boy. When the Khmer Rouge, the target of Nixon's B-52s, managed to overrun Phnom Phenh, Schanberg decided not to join the general exodus of Westerners, trusting to the aura of untouchability bestowed upon anyone possessing a Times press card and an American passport. Though Pran possessed neither of these power-laden documents, personal loyalty to Schanberg kept him from joining his family in the exodus; after all, Schanberg would have been helpless without a translator.

Sam Weterston imbues his performance of Schanberg with an appealing amount of moral ambivalence. Though Schanberg is truly fond of Pran, he is basically an arrogant American asshole journalist with a predilection for editorial moralizing. Schanberg is so narrow-mindedly hunting after a story that he cannot distinguish the larger picture from his dispatches, nor realize the consequences of his decision to stay. Anyone who has read Schanberg's column in the Times will find Waterston's interpretation convincing.

The protean John Malkovich is Al Rockoff, a gonzo Associated Press photographer. The craziest of all the leftover journalists, he is also the most aware of the real situation. In the tensest scene of the movie, Rockoff and a British friend try to doctor a British passport to allow Pran to escape. Their last minute failure is ironic enough to wrench a theater-ful of popcorn-filled guts.

The key role of Dith Pran went to Dr. Haing S. Ngor, a Cambodian refugee whose own exploits mirrored those of Dith Pran's. Perhaps his lack of thespian training accounts for the excessive Oriental inscrutability his brings to his part. But then living in the paranoid hell of Cambodia made silence and inconspicuousness golden virtues. In fact, Ngor's most effective scenes occur when he doesn't speak at all. After Pran is exiled to a rural concentration camp, he must struggle to appear nothing more than a simple peasant. His Khmer Rouge, captors, constantly suspicious, address him in French and English, unsuccessfully attempting to expose him as one of the hated Westernized Cambodians.

Director Joffe and screenwriter Bruce Davidson go to great pains to draw a parallel between Schanberg's abandonment of Pran and America's abandonment of Cambodia. When Schanberg is given an award for his Cambodian coverage, he gives a tear-filled acceptance speech laying the blame for Cambodia's agonies on the long-gone doorstep of the Nixon administration. Just afterwards Rockoff confronts Schanberg in the men's room, reminding Schanberg that the single-minded persistence that got him the award might also have resulted in the death of his friend.

The Killing Fields shares with David Lean's A Passage to India the distinction of being the most talked about and least seen film in recent memory. Start with a semi-obscure literary topic tinged with the Oriental mystery (Schanberg wrote an article about his efforts to find Dith Pran, and E.M. Forester's novel has been appeared in God only knows how many Cafe Pamplona discussions), favorable advance press in the right places, and a restricted New York-LA-Chicago distribution, and you have the makings of a film with big, big Harvard appeal.

But Joffe and Lean have other qualities in common. They both understand how to capture history on film. Lean's films (Lawrence of Arabia, Doctor Zhivago, and now A Passage to India) synthesize a coherent narrative inside of a wide vision of history. Joffe has mimicked many of Lean's techniques, achieving a balance between the personal relations of the principals and their place within the larger historical upheaval. In one excellent scene, Schanberg tries to question an American official in a warehouse filled with Coca-Cola. Suddenly a mortar barrage blasts the warehouse of cans into gooey scrap, providing the answers Schanberg needed and a symbol of the tenuousness of the Western presence in Indochina.

Unfortunately Joffe and Davidson have not managed to create a whole movie, but two separate ones. The first movie is the better one; it ends when Pran is forced to leave the French embassy. The second movie posed a critical formal problem to its makers: how to balance Pran's efforts to get out of Cambodia with Schanberg's campaign to find him.

Joffe and Davidson chose to cut between Pran's privations and Schanberg's searching's, contrasting the objective desperation of Pran's position with the psychological desperation of Schanberg's guilt. But since Pran was not allowed to talk and independent thought was considered a crime, Joffe uses voice overs, mental "Dear Sidney" letters to expose the action and Pran's reaction. The technique backfires, and they might have been better off leaving off the whole section in Cambodian. A more intelligent solution would have been to use subtitles, letting the vicious regimentation of the Khmer Rouge speak for itself.

Joffe would also have been better off to let the movie speak for itself, rather than imposing a sappily obvious soundtrack. As Pran escapes through a Cambodian countryside literally littered with bodies, the gloomy music almost turns the horror into self-parody. Puccinni and John Lennon do not belong in the same movie, ever.

Joffe's and Davidson's defects drag The Killing Fields under the threshold of cinematic glory. But its tough, unsparing depiction of two witnesses to one the 20th centuries greatest tragedies excuses the occasional cinematic botch-ups. The Killing Fields has the courage of its convictions, an encouraging case of substance winning over style.