"NEVER BEFORE, it seems safe to say, has pure, untested theory played such a decisive role in world affairs," Jonathan Schell wrote in The Time of Illusion, a book he published in 1975. Since the appearance last year of Schell's best seller about the prospective apocalypse, Fate of the Earth, books on nuclear war have become a growth industry one whose immediate future has been also seemingly guaranteed by the Reagan administration pronouncements on the subject. The sustained interest in the topic is remarkable considering the technological arcana that surrounds it, and despite the fact that-- like the moral equivalent of motherhood--the goal of preventing nuclear war is something that presumably everyone is agreed upon, at least in principle. For all the recent interest in nuclear theory, however, the nuclear theorists themselves have thus far been all but ignored. The majority of the three dozen or so "nuclear" books expected out this year will be about where we are and whither we are going in the atomic age, and not about the interesting and relevant matter of how we got here. In the escalating literature on nuclear strategy and war, these two very different books by a British professor and an American journalist stand apart, and deserve to be placed near the top of the reading list.

For most people--including the civilian strategists who would subsequently make a living thinking about the bomb--the atomic age began not on the day Hiroshima was bombed, August 6, 1945, but the day after, when news of the event appeared in the morning newspapers. While authors Freedman and Kaplan dispute who deserves pride of place as the earliest thinker about the unthinkable, both agree that credit for popularizing the concepts of nuclear strategy should go to Bernard Brodie, who was a 35-year-old associate professor of international relations at Yale on the day that the bomb fell. Brodie's reputation as a strategic thinker had already been established by two books he had written on seapower and navies; a paper he completed just before Hiroshima had predicted that the battleship was about to make a comeback. Brodie was also one of the first armchair strategists to appreciate the revolutionary significance of the atomic bomb. "All my work is obsolete," he told his wife when he read the headline in The New York Times on August 7.

Within six months of the bombing of Hiroshima, however, Brodie and his colleagues among what would subsequently be known as "the Yale group" had written a book--The Absolute Weapon: Atomic Power and World Order--that represented a first attempt to think systematically about the new subject of nuclear war. Brodie's place as a nuclear strategist would be guaranteed by three short sentences in one of the essays he wrote for the book, which became the essential statement of the theory of deterrence: "Thus far the chief purpose of our military establishment has been to win wars. From now on its chief purpose must be to avert them. It can have almost no other useful purpose."

Of course, what Brodie could not have known in 1946 was that his single qualified "almost" in the last sentence would become the basis for a debate over nuclear strategy that has now gone on for 37 years. This has been a debate between those theorists whose professional interest is with how best to avoid a nuclear war and those whose interest is with how such a war might be fought and, perhaps, won. It is not a debate between alternative strategies, but over where the emphasis in strategy and planning should be. It is a debate between the deterrers and the war-fighters, or --as it has become more recently and polemically known, between the MADmen (for mutually-assured-destruction) and the NUTS (for nuclear-use-theorists).

In retrospect, it seems inevitable that other theorists would soon dissent from Brodie's neat formulation. The basic concept of deterrence--with its assumption of stalemate--appeared contradictory to the dynamic nature of strategy. Both technological innovation and the continuing enmity of Russia and the United States in the Cold War have, as well, militated against the concept of deterrence since Brodie and his colleagues expressed it in their book. Not long after The Absolute Weapon appeared, rival strategic thinkers-- such as Albert Wohlstetter of the Rand Corporation--pointed out how a retaliatory force that was vulnerable might actually provoke rather than deter an enemy attack. It could only be a matter of time before still other theorists drew the logical conclusion that the best way to ensure the survival of one's own forces might be by striking first to disarm the other side. Gradually--almost imperceptibly --the emphasis in nuclear strategy shifted from preventing a nuclear war to fighting and winning one.

Ironically, Brodie himself would come to embody the intellectual split between the deterrers and the war-fighters. Becoming a consultant to the Air Force's planning staff after he left Yale in 1948, Brodie flirted briefly with the notion that destruction in a nuclear war might be kept limited if both sides agreed to hit only military targets, deliberately avoiding cities. Brodie, however, abandoned the idea of a no-cities or a purely "counterforce" strategy when he calculated that up to 2 million civilians would nonetheless be killed on each side in such a war. By 1950, when he joined Rand, the the Air Force-sponsored think tank, all of the assumptions Brodie had made four years earlier about the atomic bomb -- that it would remain a bulky, expensive, and relatively scarce weapon in world arsenals --were already being overtaken by technology and events. The advent of the hydrogen bomb two years later was yet another shock to Brodie and his concept of deterrence. (Rand colleague Charles Hitch told Brodie that The Absolute Weapon had been the right title for his book, but it was about the wrong bomb. By 1954, because of the H-bomb, an attack that killed only 2 million civilians became the definition of a purely counterforce strike.)

Not surprisingly, Brodie came to the conclusion that his chosen profession had hit an intellectual dead end, and that strategy and unlimited war were "simply incompatible concepts in a world of H-bombs." Thereafter his interests shifted to the possibility that even a nuclear war might be kept limited if the combatants could agree not to use world-ending weapons like the hydrogen bomb. But neither Brodie nor his fellow strategists ever developed much confidence that such a war would actually remain limited. Ultimately, Brodie lost interest in nuclear strategy altogether, devoting his study to the psychological causes of war after he left Rand in the '60s to teach at UCLA. By the time of his death in 1978 he had backed away from his earlier faith that nuclear war could be prevented, or limited once it began.

Both Freedman and Kaplan use the strategists themselves to chronicle the intellectual history of nuclear strategy, but each does so in markedly different ways. Freedman's book, which is based primarily on the theorists' written work, is the more complete and scholarly of the two. Professor of war studies at the University of London, Freedman properly traces the evolution of nuclear strategy from its origins in the strategic bombing doctrine of the Second World War. (Mathematician Freeman Dyson who worked for Britain's wartime Bomber Command, has written that "Hiroshima was an afterthought." Dyson's comment is an exaggeration, but it contains an element of truth. Hiroshima was, rather, a culmination.) In endeavoring to be comprehensive, however, Freedman has included chapters in his book on Russian, European, and even Chinese nuclear strategy that don't do full justice to their subject, and has in the process given too short shrift to the intellectual contribution of some prominent American strategists.

Kaplan, on the other hand, has written a book that is as much about the strategists themselves as about their theories. He seems to have talked to virtually everybody who is or has been anybody in the realm of nuclear strategy--160 people altogether-- and he has also performed a great service for future scholars in the Sisyphean task of getting government documents declassified through the Freedom of Information Act. His book is at times perhaps more an anecdotal than an intellectual history, yet it contains much that is not only new but stunning about the nation's official thinking and planning for nuclear war. One of the more remarkable episodes recounted in the book, for example, concerns the briefing in 1961 of Defense Secretary Robert McNamara on the Strategic Air Command's plans for a war with Russia. McNamara was aghast to discover not only that the Air Force planned to kill over 300 million Russians and Chinese at the outbreak of hostilities, but that the civilian populations of neutral countries and even allies might be enveloped by the fallout pattern resulting from the American attack. McNamara was also shocked to learn that SAC intended to obliterate the entire country of Albania because of an air-defense radar located there. (SAC commander Thomas Power told McNamara, according to Kaplan, "Well, Mr. Secretary, I hope you don't have an friends or relations in Albania, because we're just going to have to wipe it out.") Kaplan confirms that nuclear war was not unthinkable to the coterie of Rand alumni who became the "Whiz Kids" of the Kennedy-McNamara years. A nuclear "demonstration" or warning shot was considered at the time of the 1961 Berlin crisis by Kennedy strategists, and two top experts even advised the administration on how the United States might be able to disarm the Soviet Union in a nuclear first strike.

Occasionally, the fascinating stories that Kaplan can't resist telling about the strategists threaten to take control of the narrative, making it rambling and repetitive. Unlike The Best and the Brightest, David's Halberstam's book on the architects of America's policy in Vietnam, there seems to be no dominant or guiding theme in either Freedman's or Kaplan's account of the nuclear strategists. Yet one such theme that suggests itself is the excessively narrow and politically naive world of the strategists, whose obsession with military hardware has tended to equate capability with intent. Kaplan recounts how Albert Wohlstetter in the early 1950s spun highly imaginative scenarios of Russian sneak attacks that could destroy SAC's bombers on the ground. In a 383-page report on SAC's vulnerability for Rand, Wohlstetter took account of such esoterica as the flow rate of hydraulic taps at U.S. Air Force bases and the radar reflection caused by a bomber's propellers--but ignored entirely the question of how likely the Russians would be to launch their planes on a one- way suicide mission just to start a nuclear war. (SAC strategists, it turned out, were unconcerned about the vulnerability of their bombers on the ground since they intended to land the first blow in any case.) Similarly, Freedman notes that strategist Herman Kahn unwittingly undermined his argument for fallout shelters in the 1960s by enthusing about how even New Yorkers could survive a nuclear war by tunneling a thousand feet beneath the streets of Manhattan.

Admirable as both books are, simply the scope of the subject would seem to defy a definitive account in just one volume. A previous effort by a nuclear strategist himself ran to four volumes and has yet to be published. Not included in either Freedman's or Kaplan's book is the role of the atomic scientists in the development of nuclear strategy--though the division within the scientists between arms- racers and arms-controllers since the feud of Edward Teller and Robert Oppenheimer has matched in significance the strategists' debate.

A more basic criticism of both books is that neither really answers a fundamental question that should be asked about the strategists: How much difference have they made? As each author admits, Robert McNamara often used the strategists' abstruse theories only as a post hoc justification for actions taken on other, pragmatic grounds. McNamara had read just one book on nuclear strategy by the time he came to the Pentagon, but he subsequently would have the greatest impact of any individual upon American nuclear weapons policy. The major decisions on defense made during McNamara's tenure--including the size of the U.S. retaliatory "triad" (bombers, missile-firing submarines, and land-based ICBMs), the development of new weapons like the ABM and MIRV, and even the now-notorious concept of "mu1 otually-assured-destruction"--all seemed to be shaped more by technological and political forces than by the seminal thoughts of the academic strategists.

What was true of Kennedy and McNamara might also be said of their successors. More than once, it seems, the arms race has been given a spur because the weapons themselves took on a life and a reason-for-being all their own, with results that have mocked thinkers and planners alike. One of the crowning ironies of the atomic age would thus seem to be that the two leaders who came closest to espousing a kind of nuclear pacifism in their time --Robert McNamara and Jimmy Carter --each initially toyed with the idea of reducing America's nuclear arsenal to a "minimum deterrent" force composed of the missiles on just two submarines, and both ended up pushing the nation's nuclear strategy closer toward an acceptance of the theory that it might be possible to fight, and win, at Armageddon.

Freedman and Kaplan each succeed in showing how strategic thought has evolved to this outcome. But--like evolution itself--the process has not been particularly rational, and the end result may not be the cause for joy. The war plan that Brodie worked on in 1948 had only 50 atomic bombs to drop on the 70 Soviet cities that were then considered targets; its present-day incarnation identifies 40,000 potential targets in the Soviet Union and assigns 25,000 nuclear weapons to their destruction. Unsurprisingly, both authors conclude on a note that is critical of their subject, the strategists. Both also end with the rather despairing observation that it is the war-fighters who have become ascendant in the strategic debate. Deterrence, to be sure, remains the first premise of American nuclear strategy. But it is a premise that is no longer upheld with the same confident air that Brodie gave to it in 1946--as recent statements by Mr. Reagan have shown. While Freedman concedes that it is remarkable deterrence has lasted as long as it has, his final word on the current state of strategic thought paraphrases a famed observation about the charge of the doomed Light Brigade in the Crimean War: "C'est magnifique, mais ce n'est pas la strat,egie." The spirit of Kaplan's conclusion is similar: "The nuclear strategists had come to impose order--but in the end, chaos still prevailed."

The outcome of the strategic debate in this country seems all the more ironic when it is considered that the deterrers have not been vanquished--as Freedman points out, Brodie is yet to be proven wrong--so much as they have simply chosen to desert the field. As well, the nuclear gnostics who have become the confounders's of MAD have been unable thus far to come up with a more attractive alternative beyond the dubious prospect that victory in a nuclear war might be possible . . . if. Freedman and Kapland suggest in their books that the loss of faith in the nuclear strategy of deterrence has been the result of a loss of faith in the strategists themselves. Vietnam was perhaps the occasion for the beginnings of doubt --when the same strategists who had confidently written about signaling intentions and controlling escalation in a nuclear war were seen to have fundamentally misjudged the nature of the adversary in a real-life conflict on an infinitely smaller scale. Vietnam also demonstrated that behind the strategists' abstract and qualtified scenarios were basic but unremarked assumptions concerning morality, national prestige, and will. The 1969 ABM debate was probably the first significant sign of the public's loss of faith in experts and expertise, but the nuclear-freeze movement might also trace its intellectual roots to the impact of the Vietnam war.

The books by Freedman and Kaplan will focus attention upon a group of experts whose ideas have been much discussed in the national reassessment of nuclear weapons policy, but whose contribution to that policy has not hitherto been the subject of study. Such attention has been long deserved but slow in coming. The portrayal of the nuclear strategists in these two accounts also suggests that the thinkers about the unthinkable may come to share the fate of those who have made the unthinkable possible--the atomic scientists. It was one of those scientists who had had a glimpse into that fate when he exclaimed upon the explosion of the first atomic bomb: "Now we're all sons-of-bitches!"