IN HIS NEW book, Rethinking the Soviet Experience, Professor Stephen F. Cohen portrays himself as an iconoclastic warrior, battering down the rigid walls of orthodox Cold-War Sovietology -- i.e., the body of historical-political writing about the Soviet Union published from the late 1940s to the mid-1950s -- and raising aloft the banner of revisionism -- a term applied primarily, but not exclusively, to the generation of scholars who chose their dissertation topics toward the end of the 1960s. At that point, Cohen laments, there was such an "unhealthy" scholarly consensus that it was assumed "all the big questions" had been answered. "What remained for bright ambitious newcomers?" he asks.

The "intellectual crisis" facing the young scholars was resolved to some degree by the flood of new material emerging from the Soviet Union as a result of de-Stalinization, both in censored official journals and in uncensored samizdat writings. This made it possible for revisionist historians and political scientists to replace what Cohen describes as the "gray stereotypes" of traditional Sovietologists who believed in an "immutable Soviet system" with the "multicolored realities" of a changing system.

At the same time, Cohen carefully disassociates himself from the school of revisionists who, with their reluctance to study anything that cannot be counted, their jargon-ridden prose, and their deliberate exclusion of moral values, have denied the importance of history in political studies -- surprising as that may seem to the general reader, says Cohen. "Unless political analysis is rooted deeply in real historical knowledge," he asserts, "it will be marginal, sterile, or wrong."

In this sense Cohen is a traditionalist. His writing is clear, lively, often anecdotal, his ideas stimulating, though not always as unorthodox and far from the mainstream as he would like us to believe. The five essays in this book, four of them published in previous collections, are based on a thorough knowledge of Russian and Soviet history and familiarity with the field: over one-fourth of the book consists of detailed, highly readable footnotes. Cohen, a professor of Soviet politics and history at Princeton University, is generous to individual colleagues, even those he criticizes -- though his tone on occasion can be condescending. At one point he remarks, "We must marvel that Sovietologists managed to accomplish so much good empirical scholarship in such an interpretative straight-jacket." But more on this point later.

Nonspecialists will find particularly interesting the essay on Bukharin, one of the original Bolshevik leaders executed by Stalin during the purges of the 1930s, and the subject of Cohen's major work, Bukharin and the Bolshevik Revolution. Cohen sees Bukharin as Lenin's true heir and the symbol of a "lost alternative" to Stalinism: a moderate, gradualist approach to modernization in a one-party communist dictatorship. Bukharin's "afterlife" serves as a barometer of post-Stalinist Soviet history. When Khrushchev opened the prison doors in 1956, Bukharin's widow was released after 20 years in labor camps and reunited with her son, an infant at the time of Bukharin's execution. Together they tried to win complete exoneration for Bukharin, but Khrushchev was too timid to offer any more than a partial rehabilitation, later withdrawn by Brezhnev. In 1978, the 90th anniversary of Bukharin's death and the 40th of his execution, his son launched a campaign for full rehabilitation that won the support of the influential Italian Communist Party and other West European parties -- but their appeals were ignored by the Soviet government. Still, Cohen reports, Bukharin's ideas -- especially regarding the importance of market forces in a mixed economy -- have been revived throughout the communist world: in East European countries and, most recently, in China, where they are discussed openly; and even in the Soviet Union, where Bukharin is never mentioned officially by name.

COHEN, UNDERSTANDABLY, cheers on the advocates of these ideas in the Soviet Union: the reformers who look to the fluid 1920s for inspiration, against the conservatives who take their text from the rigid Stalinist 1930s -- but without the mass terror. He draws a distinction between the radical dissidents, who want the entire system replaced, and the reformers, who want to "improve the exisiting order." In his essays on Khrushchev's de-Stalinization campaign and the "conservative backlash" that followed it, he draws heavily on the work of a leading reformer, Roy Medvedev, a maverick dissident who is harassed but still allowed to live and work in Moscow.

Claiming that most Sovietologists pay too much attention to high-level Kremlin politics and too little attention to "forces and trends in officialdom or Soviet society itself," Cohen sets out to remedy the situation. He argues that the disagreements and wide array of opinion revealed in unofficial samizdat writing also exist in official circles, which are engaged in an ongoing debate between reformers and conservatives. Since the reformers are a small group, their only hope, as in czarist times, is to persuade their conservative colleagues to initiate "reform from above." The "main obstacle to change" -- and the source of the stability of the problem-plagued system -- is the "profound conservatism" of the mass of the population. This is primarily the result of their own "traumatic" history. They have suffered enough upheavals in their lifetime; they are proud of what they have accomplished and fearful of any further sudden change.

These are interesting observations, but hardly startling. In his determination to be different, Cohen occasionally ends up in an awkward spot. He argues, for example, that those who see a "gulf separating political officialdom and society" are wrong. One wonders if he would make the same statement about the Stalinist period, when the employment picture was the same.

Which brings us to Stalin -- the "accursed question" -- a phrase that was used to refer to serfdom in the 19th century. The dispute about the meaning of Stalinism lies at the heart of Cohen's assult on the "orthodox totalitarianism school" and its "consensus" view of Soviet history. His assault is meant to provoke debate; still, many of his charges are exaggerated, and there are times when, in his eagerness to demonstrate the "simplistic" approach of his predecessors, he fails to give a fair account of their views.

Anyone re-reading some of the landmarks in the field -- by Merle Fainsod, Leonard Schapiro, Adam Ulam, Bertram Wolfe, Richard Pipes, George Kennan, to mention only a few -- or leafing through 20 years of the journal Problems of Communism -- finds not an "unhealthy" consensus but a variety of vigorous viewpoints; Cohen, however, dismisses them as "disputes over secondary issues" and "efforts to refine the consensus."

The crucial issue for Cohen is the relationship between Stalinism and the rest of the Soviet experience. He charges that the "totalitarianism school" sees Stalinism as part of a "straight line" that proceeded inexorably from Lenin's pre-revolutionary ideas about party organization. He cites Fainsod's famous line -- "Out of the totalitarian embryo would come totalitarianism full-blown" -- as typical of this "orthodoxy." But he seems determined to deny the complexity of Fainsod's analysis and that of his colleagues.

For example, while quoting a long list of scholars who comment on the obvious connection between Leninism and Stalinism, Cohen quotes Alfred Meyer, who wrote, in Leninism: "Stalinism can and must be defined as a pattern of thought and action that flows directly from Leninism." But there is more to Meyer's statement than that. Cohen igrnorss the fact that Meyer also says, on the same page, "Stalin's opponents, who came to stress the democratic aspects of the party's traditions, could base their arguments on the Leninist writ, just as Stalin's successors, in repudiating one-man rule and in stressing collectivist practices, are no less Leninist than was Stalin." Then, after reviewing the ways in which "Stalin has trod in Lenin's footsteps," Meyer repeats, "the many non-Stalinist or anti-Stalin interpretatins are derived from the same Leninism which gave birth to Stalinism." Meyer's point, made in 1957, anticipates by some 20 years Cohen's major argument about "lost alternatives." As Cohen puts it, Bolshevism contained the "seeds" of Stalinism but "it also contained other important non-Stalinist 'seeds.'"

COHEN MAINTAINS that Stalin represented, not "fundamental continuity" with the Bolshevik tradition, as the "orthodox" school would have it, but a major discontinuity. He does not quite call Stalin an aberration, but he comes close. Referring to Western scholars who speak of a "Stalinism without the excesses," Cohen says, "Such formulations make no sense. Excesses were the essence of historical Stalinism." He explains, "Stalinism was excess, extraordinary extremism." It was not . . . merely coercive peasant policies, but a virtual civil war against the peasantry; not merely police repression . . . but a holocaust by terror that victimized tens of millions of people for twenty-five years." Where others see a difference in degree, Cohen sees a sharp break with the past.

Yet those who argue for a basic continuity in the Soviet system may find evidence to confirm their views in Cohen's description of the "far-reaching conservative reaction" that followed Khrushchev's de- Stalinization campaign. It has included such disturbing features as the rehabilitation of Stalin and the KGB; an increased emphasis on vigilance, discipline, and control; growing xenophobia and anti-Semitism; and, even "more ominous," according to Cohen, the "tacit rehabilitation of the notorious show trials of the 1930s" and the reappearance in print of "epithets of the terror years," such as "enemies of the party and of the people," "fifth column," and "rootless cosmopolitans." In the absence of regularized legal or consititutional procedures to act as a check on state power, what guarantees are there against a more virulent swing to the right that might eventually permit a return to the "excesses" of Stalinism?

Finally, on the last page, after devoting very little attention to Soviet foreign policy, Cohen makes a quick pitch for d,etente. There are plenty of good arguments for d,etente, but it only provides ammunition for its opponents to suggest, as Cohen does, that every time the tough guys won out in the Soviet Union -- from the war communism of 1918 to Stalin's forced collectivization and purges to the conservative reaction under Brezhnev, "a crisis or serious worsening in East-West relations played a crucial role." Cohen concludes, "The lesson is that Cold-war relations abet conservative and even neo-Stalinist forces in Soviet officialdom and that Soviet reformers stand a chance only in conditions of East-West detente." This kind of argument -- oversimplified when it is not historically inaccurate -- is particularly disappointing since Cohen prefaces it by stressing the "necessary relationship between historical knowledge and political analysis."

In the post-Stalin period alone, the decade-long triumph of Soviet reformism" at home coincided not only with the restoration of Austrian independence in 1955 and Khrushchev's groundbreaking visit to the United States in 1959, but also with the sppression of the Hungarian revolution in 1956 (only months after Khrushchev struck the first blow for de-Stalinization in his famous secret speech), as well as the Berlin crises and the Cuban missile crisis. In contrast, the easing of tension marked by the signing of the limited nuclear test ban treaty in 1963 was followed, in 1964, by the ouster of Khrushchev -- the "great reformer." And then, of course, the Nixon-Brezhnev d,etente coincided with a domestic period described by Cohen as a "long winter" for reformers.

Another advocate of d,etente, Professor Marshall Shulman, has described the latter period more accurately as characterized by "an inverse mechanism": a "policy of reduced tension abroad is accompanied by a tightening of internal controls" so that the system is not "undermined by the widening of contacts with the outside world." This is the sort of analysis one would expect from Cohen, who, on this occasion -- carried away by his wholly admirable reformist sympathies -- has lost sight of the complexity of the issues, just as he has accused his predecessors of doing throughout his provocative and stimulating book.