Disorienting leaps from reality to fiction and back again on television have become so commonplace that they aren't very disorienting any more. Tonight, exactly one year after Americans sat spellbound and fearful in front of their TV sets in the wake of an attack on the nation's chief executive, a local station offers the chance to go inside the emergency room for a painstaking reenactment of what we couldn't--or at least didn't--see on the day of the shooting: "The Saving of the President."

The docudrama raises questions of propriety and journalistic license and the proverbial right-to-know, but such questions crumble into nuisance when balanced against the excellence and impact of the film. Among the things it makes frighteningly clear is the fact that the president was in more mortal danger than the public was led to believe at the time, and this revelation could be seen as peculiarly belated. It still makes stunning television.

Washington-area viewers will have two chances to see the film this week; first, tonight at 9 on Channel 7. Then, because it is, apparently, the first locally produced news production ever to be purchased for national telecast by a commercial network, "The Saving of the President" will also be seen during a special edition of ABC's "20/20" at 10 p.m. Thursday on Channel 7.

This unusual occurrence represents a coup for the ambitious, enterprising and compulsively award-winning filmmaking team of Paul R. Fine, director and cinematographer; Holly K. Fine, editor and co-producer, and sound man Clyde R. Roller. And it celebrates a particularly auspicious medical victory for the trauma unit and the doctors and nurses at George Washington University Medical Center. But the hero of the piece is the assassin's intended victim, Ronald Reagan, who is played by 38-year-old actor Donald Williams during the reenactment but who appears as himself in a brief concluding sequence shot at the White House on Feb. 26.

Three of the doctors who had attended the president as he lay injured and gasping at the hospital called on him at the White House about two weeks after his release last April. They returned to reenact that scene for the camera, and the president agreed to participate. In the scene, he recalls cheerfully that doctors had "loaded me with a lot of other peoples' blood" while at the hospital and asks, "Am I back on my own blood now?" The resilience he exudes, particularly with the memory of last year's horror freshly re-awakened, seems heroic, nothing less. Whatever one thinks of his performance as president, he comes across again here as an extraordinary man remarkably adept at spreading encouragement. It is a rare gift, and he's got it.

George Washington University Medical Center produced and owns the film, made in conjunction with WJLA-TV. When ABC News president Roone Arledge and "20/20" showed interest, negotiations had to be conducted with the hospital. The network agreed to donate $115,000 to the tuition fund at the center's School of Medicine in return for two showings of the film, which cost only about $25,000 to make. It also agreed not to edit the film (except for the deletions of credits and a spoken prologue) and not to interrupt it--a stipulation that grew out of the hospital's original pledge to the president when he agreed to participate.

The film opens with a reenactment of the shooting at the Washington Hilton, mostly from the point of view of Secret Service agent Jerry Parr, who pushed the president into the back seat of the limousine and rode with him to the hospital. As surely everyone knows, videotape footage of the incident exists, but Fine vowed not to use any of it. "People are sick of seeing that," he said yesterday.

Most of the rest of the film takes place in the hospital, where all those seen working on the president are the actual doctors, nurses and orderlies present at the time. Only the Secret Service agents are actors (although Parr's voice is heard on the soundtrack). In addition to Williams' speechless portrayal of the president, local writer John R. Pekkanen, a consultant to the producers, plays the part of injured press secretary James Brady, who is briefly glimpsed under a sheet on another operating table. Everyone else is a real person.

For all we and television have been through together, some sights in the film are still shocking--the president walks into the hospital but then, suddenly, collapses, and falls to his knees; he is picked up and carried the rest of the way. Later, an orderly, carrying a vial, rushes upstairs to a lab, and in voice-over remembers saying to himself, "This is Reagan's blood." In the recovery room that night, the president is panicked at being unable to breathe, and he is seen writhing and trembling. We know it's an actor, but it's an actor playing a living president.

Fine does not think such sights are improper, though some viewers may be jarred even by an early scene in which the president's shirt is torn off him as the emergency team begins its work. "In fact, he was really nude," says Fine. "I tried to be as tactful as I could, but that's what they do in an emergency room. It wasn't really his body, so I don't think we're hurting the president by ripping this actor's clothes off."

The film is filled with details that are touching or startling or even lighthearted. Secret Service men have to don operating room "greens," and one of them returns from the lockers barefooted, not realizing protective coverings for his shoes will be supplied. Reagan's now-famous joking question about the political affiliations of the doctors is recounted, as is one doctor's reply that "Today, Mr. President, we're all Republicans." Because there is no handle at the foot of the bed on which the president is being wheeled into the operating room, a surgeon grabs hold of his foot to pull him along.

And then there is the dark and eerie moment when, after much probing of the president's lung, the bullet is found, and held up for the doctors and nurses to look at, their elation at recovering it surely mitigated by the sorry fact that it was there in the first place.

The film can indeed be viewed as a very positive, perhaps deceptively positive, piece of public relations for the hospital in particular and the medical profession in general. Dr. Frank Kavanaugh, associate professor at the center and executive producer of the film, said yesterday, "I don't know of any way you can get away from that." He said he thought the more important influential value of the film was its stress on the virtues of academic medical centers and on the establishment of trauma units in more communities throughout the country.

Fine said propaganda for GW was "one thing we said we would not do. We'd recreate the day and the people can form their own opinions from that." Told that the hospital and its staff come off looking exemplary in the film, Fine said, "Well they did do pretty good." Fine directed and photographed the sequence at the White House, but he did not give any direction to the president. "You don't have to give direction to the president. He's an actor. He knows. He's got that glow."

Early news stories that the president was returning to "acting" for this film, however, irritated Fine. There was no script; the president merely asked questions of the doctors while the camera rolled (for 10 minutes, of which 90 seconds was used). Fine also says Washingtonian magazine is taking more credit for the film than it deserves. Although the magazine did run a piece with a similar theme, Fine says the film is not based on it but on original research.

Dr. Dennis O'Leary, whose camera presence and medical professionalism reassured the country in the hours following the attack on Reagan, appears in the film. Fine even had O'Leary recreate his press briefings, rather than use videotape of the real thing.

There are discomforting aspects to the production, and the whole concept of reenacting such an event using many actual participants; it would be folly for the filmmakers to claim 100 percent accuracy with so many vested interests involved. It could also be argued that, even though he is played by an actor, the president's privacy and dignity were violated (a White House spokesman said yesterday that, although a cassette of the film was sent there last week by Kavanaugh, the president has not yet seen it, and it was not known whether he would watch it on the air tonight).

The film itself puts most potential objections on hold, or just obliterates them. It is a genuine, moving story of victory, of a nightmare with a positive outcome, of "My God, they've shot the president" becoming "My God, they've saved the president." One looks for hope wherever one can find it, and one can find it here.