This story is imaginary, but the technical details are based on extensive research by Walter Pincus and Robert G. Kaiser of The Washington Post's national staff.

It is Aug. 10, 1984. The new Soviet leadership is finally in place in the Kremlin. The long bickering that followed Leonid Brezhnev's death in his sleep in late 1983 produced a showdown between the so-called Mir ("Peace") and Cil ("Strength") factions in the Politburo. This longstanding split has never been publicly revealed, but it has been the crucial division in Soviet politics since the early 1970s. Brezhnev led the "Peace" faction, and it has now been beaten. The new general secretary of the Communist Party is Vladimir Ivanov, 63, a resourceful politician who ran the Ukraine for several years. The outside world knows nothing of Ivanov's plans or policies.

In fact they are ominous. His secret platform in the just-completed leadership struggle was simple: The time has come for the ultimate showdown with the imperialists. The Soviet economy is slipping badly, Ivanov argued; oil is running out; the people are restless and hungry for consumer goods; the non-Russian nationalities are threatening rebellion. Most serious, the comrades who run the Red Army are upset by the latest developments in the imperialist camp - the new American MX missile, the stationing in Europe of new ballistic and cruise missiles aimed at the Motherland of socialism, and much more. This may be the last chance to win the ultimate showdown, so we must move now. That is what Ivanov and his colleagues argued, and they won.

Soon after taking power Ivanov had called together the seven-man team under Col. Lev Perlshtein that had long been responsible for the Soviet Union's most sophisiticated strategic thinking. Ivanov asked Perlshtein and his group to produce a crash study on how the Soviet Union could initiate and win a nuclear showdown with the capitalist camp. Ivanov told Perlshtein he was expecially interested in the concept of the "window of vulnerability" that he had read about in the Politburo's private translations of American publications.

On this sticky August afternoon Perlshtein assembled his group in the Kremlin's wood-paneled situation room, four stories below the ground. He brought with him all six of his team, including Vladimir Kuznetsov, an apparatchik who had worked for almost two decades on strategic issues on the secretariat of the Central Committee. Perlshtein was particularly proud of Kuznetsov, who was his own devil's advocate, a man steeped in strategic lore whose job it was to argue against whatever course of action the colonel himself chose to argue.

Ivanov was both excited and a little nervous about this encounter. Excited because he really did hope Perlshtein could produce a workable plan. Nervous because although he had won the power struggle, the "Peace" faction was still well represented on the Politburo, and he wasn't sure he could command a majority for an aggressive policy. On this day he had invited only four colleagues to the situation room - four men who were utterly loyal to him, though only one, Marshal Nikolai Antonov, his new minister of defense, had expert knowledge of strategic matters.

The other three were former regional party secretaries like Ivanov, all of whom he had brought to Moscow in the last few months: Fyodr Trepotkin from Leningrad, Alexei Stepanov from Minsk, Archil Shevshadze from Tbilisi. All were smart; all were tough; all had helped Ivanov to power.

The room was cool, unlike Red Square that sunny afternoon. Perlshtein and his group sat on one side of the long meeting table covered with green felt and dotted with bottles of Narzan mineral water. Ivanov and his four colleagues sat across from the experts. Ivanov nodded to Perlshtein to begin the briefing. This is what he said:

"First, comrades, a warning. You have put before us an unprecedented task. No power has ever used thermonuclear weapons. (I skip over the imperialists' atomic bombing of Japan, with which you are all familiar.) Also, the attack suggested by the general secretary will require launching 350 of our rockets almost simultaneously, an unprecedented feat.

"Nevertheless," Perlshtein went on, "Comrade Ivanov has indicated he hopes to pursue this course. I intend to present our best thinking on how it could be done. We are encouraged by the extensive American literature on this subject, particularly analyses by the most determined imperialist warmongers, who are obviously convinced that we could succeed with a surprise attack.

"Let me add at the outset," Perlshtein said, "that, as usual, Comrade Kuznetsov disagrees with the thrust of my briefing. He will offer his dissent when I have finished.

"Let me outline our analysis of how a surprise attack could be launched against the imperialist camp. First, we must strike without provocation, when the imperialists believe our relations are on a sound, peaceful footing. It might be advisable to pick a moment when the Bolshoi Ballet or the Moscow Circus is touring the United States.

"There can be no hint of what we plan. They are watching us intensely by satellite, and they are listening in on our communications. Need I recall the embarrassing revelations in the imperialist press some years ago of conversations picked up from Comrade Brezhnev's limousine telephone as he drove to his Dacha? We must assume capitalist agents are well placed in our country, though we are confident they are not in our strategic rocket forces' chain of command.

"Our first aim must be to prevent America from going on any alert. With no alert we have a good chance of destroying all of their Minuteman and Tital missiles, at least half of their missile-carrying submarines and more than half of their bombers, which we would catch in port or on airfields.

"No matter what we do, you should keep in mind that the Americans' aggressive policies lead them to maintain much larger submarine missile and long-range bomber forces on alert, even in peaceful times, than we do. For example, we believe that more than 100 of their bombers can be put in the air, aimed at our homeland, within 15-30 minutes of an order to do so.

"Even without an order from the president, the notoriously reckless commanders of the U.S. Strategic Air Command can more than double this number by raising the level of alert. And American naval commanders can quickly add to the number of missile-carrying submarines at sea. In peaceful times, we calculate that the Americans usually have 350 submarine missiles at sea, carrying about 3,000 warheads. With an alert these numbers would rise."

At this point Kuznetsov, the devil's advocate, quietly interrupted his boss. "One point of information," he said. "To prevent the Americans from going on alert, we cannot go on alert. We must leave 80 percent or more of our submarines in port, where they usually are. We cannot move any bombers, including our Backfires, from their normal bases or otherwise change their behavior. We cannot evacuate any civilians. It may even be impossible for all of our leadership cadre to take advantage of the shelters that have been built for us."

"Quite right," Col. Perlshtein agreed. "But we do retain the element of surprise. To continue: The objective of this attack would be to eliminate the American land-based missiles and all of the missile-carrying submarines and bombers that would remain unalerted at the time of the strike.

"To do this we would propose firing 350 to 400 of our best long-range rockets, 200 RS20s (the one the Americans call the SS18) and 150 to 200 RS18s (the SS19). These would carry 2,450 to 2,800 warheads, each with explosive power of more than 500,000 tons of TNT. This would enable us to aim two warheads from two different rockets at each of America's 1,054 missile silos, and would give us a healthy margin to compensate for possible misfirings and to attack submarine and bomber bases."

Ivanov perked up as Perlshtein completed his description of the attack. "What was that about misfirings?" he asked. His question prompted a remark from Marshal Antonov.

"Comrade Perlshtein," Antonov said, "I think you should describe some of the technical challenges involved here."

"I was just coming to that," Perlshtein replied briskly. "As I said at the outset, we have been asked to describe an attack that no one has ever attempted. By its nature it is not something we can practice. Thus we will face a number of unique "technical challenges," to use Marshal Antonov's expression. Let me outline the principal ones.

"To be successful, this attack must be timed with a precision that neither we nor the Americans have ever attempted. Our warheads must land within seconds of each other - to be precise, within 20 to 40 seconds of each other - on each target, each of which is at least 10,000 kilometers [6,000 miles] from our missile silos. To guarantee the destruction of each silo we attack, we will want to achieve two explosions: one at ground level, one several hundred meters in the air. If the warheads arrive at their target more than about 20 seconds apart, the effects of the explosion of the first will probably disable the second as it arrives.

"To achieve this precision at the targets, each of our rockets will have its own, precise instant of launch. Each rocket will travel a unique flight path, each over a precise and unique distance, as will ch of our warheads. As you know, our missiles are based in silos that stretch across about 1,600 kilometers [1,000 miles] across our country. Naturally, our command communications to launch the hundreds of rockets in this maneuver will have to be perfected."

Ivanov perked up again. "What has happened in the past when our people have tried something of this kind?" he asked.

"We have never tried anything of this kind," Perlshtein responded crisply. "But we do have an advantage over the Americans in these matters. We have tested our missiles from operational silos, so we know how they will work in a real attack."

"How many have we tested at one time?" Ivanov asked.

"Usually one at a time," Perlshtein replied. "Never more than 10."

"But what about the misfirings you mentioned?" Ivanov asked.

"That is another matter," Perlshtein said. "We know from experience that some rockets will fail to ignite, fail to stock to their course, or fail to go off on time. For this reason we will fire more rockets than we think we need - a margin of safety, if you will."

"Another point of information," Kuznetsov interjected. "Col. Perlshtein has told you that some rockets - we estimate 10 percent, by the way - will misfire. Unfortunately, we cannot predict which rockets these will be. But all our rockets must be targeted in advance. This means the targets of those rockets that misfire will not be hit, or will be hit with only one warhead. But we will not know which targets these might be, so we will not know where to target the extra missiles we plan to fire to provide the "margin of safety." In summary, we have to adknowledge that we will miss some targets."

"Thank you, comrade," Perlshtein remarked. "Let me continue.

"Obviously, our attack must be based on the assumption that our rockets and warheads are now as accurate as even the Americans' best. We believe they are. Also, because our warheads are bigger than the Americans", we can be more confident they will actually destroy the U.S. silos, because they will have such enormous explosive power. As you know, we now believe we can hit any target in America within a margin of error of 300 meters [about 1,000 feet].

"Before Comrade Kuznetsov offers another point of information, let me explain one small problem regarding accuracy. This is a matter that have never been discussed by even the Americans in public, but our intelligence has discovered that the Americans refer to the problem as "bias."

"As some of you may know, during our rocket tests we have always had some difficulty hitting the planned target, particularly in early phases of testing. Our mathematicians tell us there are geodetic anomalies that can distort the flight path of a missle or a warhead. That means a flight path over the ocean will not be the same as a flight path over mountain ranges with high iron-ore content, to give an example. Of course you all remember that the earth is not a perfect sphere but a slightly distorted one. This too can influence flight paths.

"We have compensated for this by adjusting our targeting mechanisms. Now, when we fire our rocket systems from west to east, we can hit targets with the anticipated accuracy. Some pessimists among our scientists believe that when we fire missiles over the North Pole at the United States, we will discover that our computations no longer apply, that new factors we have never experienced will distort our flight paths. Obviously we cannot test this hypothesis."

"What do the otpimists say?" Ivanov asked.

"They don't think these factors could take us far off target, and that the large explosive power of our warheads should compensate for whatever error occurs," Perlshtein said.

"A point of information," Kuznetsov interjected. "I think the Americans use the word "bias' precisely because it is an irrational, unpredictable factor. In the end our mathematicians could not explain the constant and consistent error in our targeting systems that our test flights revealed. We have just made an arbitrary compensation in our aiming. We don't know why we always went off target before."

This exchange elicited the first comment from Trepotkin, the former party boss from Leningrad. Had he the gift of candor, Trepotkin would already have admitted that this entire meeting was quite astounding. Instead he asked Perlshtein a question:

"I'm not sure I understand," he said. "Is Comrade Kuznetsov saying that we won't be able to hit the targets?"

"No, no," Perlshtein replied. "Comrade Kusnetsov is saying there is some possibility - some unmeasurable possibility - that we won't hit the target with each warhead."

"We might miss the targets," Kuznetsov said in a low voice. Perlshtein ignored him.

"While we're talking about targets," Marshal Antonov commented, "perhaps you should discuss what the Americans have been doing to protect their missile silos."

"I was just coming to that," Perlshtein replied. "The Americans have recently completed what they call the "hardening" of their Minuteman silos. This involves building thick barriers of concrete and steel around each silo. The Americans claim these silos can withstand pressures of 2,000 pounds per square inch. If true, this would mean they have good protection against anything but an almost perfect direct hit. Unfortunately, the atmospheric test ban treaty prevents us - and the Americans - from knowing exactly how strong these hardened silos might be. We can't test a real silo with a real bomb in normal conditions. It seems possible the silos are only half as strong as we think."

"Or twice as strong," Kuznetsov observed.

"Let me continue," Perlshtein said. "Of course this attack will not occur in a vacuum. We have also studied the political environment. Specifically, we have considered how the American president might react.

"We conclude that American satellites will detect our first barrage of 100 or more rockets as soon as they have taken off. Infrared detectors on satellites that hover in space 25,000 miles above our territory provide that information, and it is impossible for us to eliminate those satellites. That information will go through military channels to the White House, and it is supposed to reach the president almost instantly. But, as Dr. Kissinger and others have noted, it may not be easy to find the president at once.

"But we must assume he would get word of the attack within minutes. At first he will probably question the report, since he will see no provocation for an attack. Indeed, for the same reason the American military might withhold the information for further checking before passing it to the president. But this initial confusion could not last more than five minutes or so, because the Americans will soon detect our second and third barrages, and their radar will begin confirming what their satellites have told them already.

"As you know, the American system is poorly designed. The president alone can order a nuclear attack. But we assume he would inevitably consult with his ministers and perhaps some members of Congress. He would also have to flee at once to the airplane set aside for his use as a command post during an attack. We assume the president would also try at once to contact you, Comrade Ivanov, on the hot line. All these things take time. We have high confidence that the southernmost missile silos would be destroyed by the time the president could satisfy himself that he knew what was going on. I am talking of a period about 30 minutes after the initial launches.

"This is the crucial moment. By our calculation it will take another 30 minutes to complete our attack. The president will realize what we are doing. He will also realize that we have avoided attacking any major city, even Washington. The Americans have done studies on this kind of attack and they know that it will cause minor losses - perhaps 10 million people, perhaps 20 million."

Ivanov started at this last observation. He recalled the Great Patriotic War [World War II], when the Soviet Union was largely laid waste and 20 million people were killed. "Are you saying that 20 million dead is a minor loss?" he asked.

"Only by standards of nuclear war," Perlshtein replied. "We calculate that by targeting the American population, we could easily kill 150 million. The president knows this too. He will see it is a minor attack.

"To continue. The president will have to realize that if he retaliates with his remaining forces - the bombers that have escaped our attack and the missiles on submarines - he will use up most of his remaining weapons and can only strike at our cities and industry. Without land-based rockets, he won't have weapons of sufficient accuracy to fire at our remaining land-based force.

"But this is a horrible option for the president. If he exercises it, he knows that we will retaliate, and both our countries will be destroyed. But if he holds back and tries to negotiate, he can save his country - maybe even save the world. American presidents are romantics. We assume he will opt for negotiation, which of course will amount to surrender. And I might add, this is just what many American experts have predicted.

"We assume he will opt for negotiations," Kuznetsov interjected, "because we have to assume so. Otherwise our attack will fail. We would lose our country if the president decided to retaliate instead."

"Yes, yes," Perlshtein replied. "That is a hypothetical possibility."

Perlshtein put down his notebook and opened a bottle of Narzan. The bubbly water spilled into his tumbler. While he took a drink Marshal Antonov scribbled a note and passed it to Ivanov. The general secretary read it and turned to Perlshtein:

"I would like Marshal Antonov to ask a few questions. Marshal?"

"First let me say that Col. Perlshtein has done his usual fine job. Then let me ask some questions. First, colonel, as you know, if we saw an American attack coming at our missile silos, we would immediately launch our rockets, so they would not be in their holes when the American warheads arrived. Why wouldn't the Americans do the same thing? I know they have written about this idea as something called "Launch Under Attack." I remember my friend Harold Brown threatening to do just that."

"I am grateful you raised that point." Perlshtein replied. "Our people are dubious that the Americans are well-enough organized to launch under attack. Remember, they will be caught completely by surprise. And although I grant they have written and talked about this possibility, we have seen no sign that they have adopted it as a strategy."

"But what if they only began to launch their missiles after the first of ours had landed?" Antonov asked. "Couldn't they still fire off more than half of their land-based rockets before we could destroy them?"

"That is a hypothetical possibility," Perlshtein replied.

"On another matter," Antonov said, "during this attack, what happens to America's bombers in Europe and on their aircraft carriers - what we call the forward-based systems in SALT talks? Don't we know that at least 200 of them are on 15-minute alert, and can carry their nuclear weapons to our homeland in less than an hour?"

"We have two options," Perlshtein replied. "We could target those bombers with our medium-range missiles, wiping them out simultaneously with our attack on the American missiles. But this would mean destroying much of Western Europe, so we rejected that idea. No, we must assume that the president would be as reluctant to use these weapons as any of his others."

"Let me ask about the number of American missiles that might survive our attack," Antonov went on. "I gathered earlier that we assume that even if our attack goes very well indeed, we would miss 10 percent - about 100 missiles. Ist that right?"

"Right," Perlshtein replied.

"And how did we arrive at that figure?"

"It's a mathematical probability, marshal. Our people say it is the sort of failure rate we could expect."

"Could it be 20 percent, or 30?"

"I don't know how to answer that, marshal. Ten percent is a hunch. Twenty percent could be another hunch."

"You mentioned that some American bombers would take off before we could destroy them on the ground. Wouldn't some of these bombers be the newly fitted type that can carry 20 of the most accurate cruise missiles? Wouldn't all of them at least carry potent bombs? What would happen to them?"

"Again, marshal, we have to assume that the president would decide not to use those weapons," Perlshtein replied.

"You'd also have to assume that there are no Dr. Strangeloves - wasn't that the name?" Kuznetsov interjected. "I mean, you have to assume that none of those American pilots would take it upon themselves to retaliate against the Soviet Union."

"Americans usually obey orders," Perlshtein replied.

"I should ask the same question about the Americans' submarines. You said, I believe, that there would be more than 20 of them hidden at sea during and after our attack, with more than 3,000 warheads?"

"Again," Perlshtein said, "we have to assume the president won't try to use them."

Perlshtein sat down and opened another bottle of Narzan, nodding toward Kuznetsov as he did so. The man from the Central Committee took the cue. He shuffled his notes and began to speak.

"My assignment, comrades, is to argue the weaknesses in the briefing you have just heard. Speaking frankly, I'm not certain that you need to hear any more arguments against this idea, but please permit me to add on or two new points, and then to summarize what Marshal Antonov has referred to as the technical challenges.

"All of us are familiar with the consequences of conventional warfare on a nation. The general secretary has already recalled the sufferings of our Motherland 40 years ago, from which we are still recovering. I would remind the group that we are talking about something quite different. Perhaps this is something I am especially well placed to discuss. On Comrade Khrushchev's instructions, I was present in July 1962 when we detonated the largest hydrogen bomb ever exploded - about 50 megatons, you will recall. Let me assure you that all of what the Nazies did to our Motherland did not compare with this one explosion. And the "minor attack" Comrade Perlshtein has outlined involves the explosion of about 1,350 megatons in the center of the United States.

"I have inquired at the Academy of Sciences: Do we know what the effects of such a powerful attack would be? (Here I have in mind not the military consequences, but the impact on the land, the air, the atmosphere and, of course, the population.) The answer is, we have theories but no real idea. We have no idea whether we might crack the earth's surface, or permanently damage the ionosphere, or poison the air over the entire world. I am referring here to consequences that could affect us at home - I happily set aside consequences for the United States. I am referring also to political consequences. Comrade Perlshtein implies that the American president would react to damage on this scale by doing nothing. That is not the way we reacted to Nazi devastation of our country. I do not think we can conclude that only Russians would react as we did to such devastation of the Motherland.

"In passing, let me note another point. Comrade Perlshtein has described an attack on the heartland of America. That, as you know, is the area that produces America's great grain harvests. For years even we have depended on those harvests. I did learn at the Academy of Sciences about the Americans' findings in the South Pacific, where they once tested thermonuclear weapons. Thirty years after the fact, on the site of much less devastating explosions than Comrade Perlshtein has proposed, the earth remains so poisoned with radioactivity that the food it produces contains unacceptable levels of radiation.

"But these are hypothetical matters, about which the best scientists can disagree. For myself, I am more concerned about those "technical challenges." Frankly speaking, I do not see how we can surmount them. Let met add that I do not believe the Americans could surmount them either.

"Let me review them briefly. Comrade Perlshtein asks us to consider an attack that would require perfect timing of a command system that has never been tested; that would assume a level of reliability of our rockets that is extraordinarily high, especially when we consider that most of our rockets have been sitting for years - by necessity untested - in silos; that would require salvos of hundreds of rockets when we have never experimented with such salvos; that would require accuracy that depends on untested mathematical formulas, and whn we know for certain that the earth's magnetism and atmosphere have unforeseen effects on rocket trajectories; that assumes we know how well American has protected its silos, when in fact we cannot know; that assumes we understand the effect of one thermonuclear explosion on a second, incoming weapon, when we don't really know those effects; and, most crucial - and, in my view, most debatable - that assumes that having suffered this attack, the American president will react by doing nothing with the enormous arsenal he would retain even after the attack. Moreover, we must assume that even if the American president did do nothing, the notoriously reckless American military would obey his orders.

"Of course I may be wrong. It remains possible that the American president will do nothing. But as Lenin's heirs and leaders of the Motherland, we must think of the problem from the opposite point of view. What if we guess wrong? What would the consequences be if instead of doing nothing, the president opts for aan all-out response?

"We know the answer. The Americans could launch many land-based missiles during our initial attack, and these alone could destroy our industrial civilization or many of our own rockets. Their submarine missiles and bombers could continue to strike at us for hours or even days, eliminating most of our population. Yes, we might take some satisfaction from the fact that we retained powerful rockets of our own, but what will we have won? What is the gain? Both of our countries could be destroyed."

It was Kuznetsov's turn to open a bottle of Narzan. Perlshtein took advantage of the pause to speak up again:

"Comrades, please keep in mind, the proposals Comrade Kuznetsov attributes to me were not my idea. I came here today to fulfill an instruction, to present a hypothetical plan. This whole idea grew out of articles the general secretary read in the American press. It is the Americans who have always trumpeted this proposal - American generals, American cold warriors. As Marshal Antonov will confirm, our military people have never put great stock in these ideas. Frankly speaking, I am not prepared to give answers to all of Kuznetsov's points. I have searched for similar arguments in the American literature on these subjects, but to no avail. The Americans have not questioned the idea of their own vulnerability as forcefully as Comrade Kuznetsov has questioned it."

General Secretary Ivanov did not reveal his personal disappointment with the course this briefing had taken. Instead he asked Perlshtein a question:

"Let us assume you are right, that we really could not afford the risks inherent in this adventure. Still, could we exploit the Americans' belief in this theory to our advantage? Could we somehow threaten this attack to win other important objectives?"

Col. Perlshtein volunteered a reply: "Yes, Comrade Ivanov, we can use the threat, but I think we must be honest with ourselves about the fact that we can never fulfill the threat. That means we cannot invoke it to try to defend our own central interests. We might invoke it - even without saying anything - in areas like Angola and Ethiopia."

Kuznetsov intervened: "I might recall that we achieved our objectives in Angola and Ethiopia at a time when we did not enjoy this theoretical "advantage." We achieved our objectives in Berlin in 1961 when it was the Americans who had this kind of superiority,""

"Well," said Ivanov finally, "at least we know we have this card to play in a crisis - if we find ourselves caught with the Americans in an escalating confrontation in the Middle East, for example."

"I think not," Kuznetsov replied. "In a real crisis the Americans would be on a high alert. We would lose the element of surprise. Our attack could not be even as effective as the one outlined by Col. Perlshtein."

With that the room fell silent. Ivanov gave no hint of embarrassment as he crisply thanked the briefers for their presentation. As the meeting broke up, Ivanov turned to Marshal Antonov. "I hope you will be ready next week with the briefing on lasers and particle beam weapons," he said. CAPTION: Illustration 1, no caption, By Robert Barkin - The Washington Post; Illustration 2, no caption, By Geoffrey Moss for The Washington Post; Illustration 3, no caption, By Tony Auth - The Philadelphia Inquirer