Soviet diplomacy, as seen from the inside. Ex-envoy's account is more telling now, in light of succession

``While they are predatory, they are not mad.'' This is one of the most significant statements in this defector's book about Kremlin leaders, motives, perspectives, and policies -- a book that has been on the US best-seller lists for a number of weeks now.

It comes in a passage in which Arkady Shevchenko tries to illuminate Kremlin thinking to Westerners from his background as the highest-ranking Soviet diplomat ever to switch sides.

The statement, and the book itself, seem more interesting today than when they first appeared earlier in the year.

In Washington and dozens of other capitals, the new and relatively young leader, Mikhail Gorbachev, is the object of intense speculation and maneuvering. What kind of man is he? Can we expect Old Guard Kremlin thinking to shift now? If so, how?

It is Mr. Shevchenko's view that the Soviet Union will not risk a nuclear war with the United States because such a war would invite destruction of the USSR itself and all the gains of which the Kremlin is extremely proud.

He believes, however, that Moscow is prepared to risk limited regional and local wars to expand its influence worldwide. The Soviets keep piling up ever-newer nuclear weapons -- not to detonate them on a battlefield, but to use them as a ``political instrument of pressure, to intimidate and blackmail . . .'' and because Moscow never forgets the ``specter of China.''

Only US military and economic strength, only American energies, convictions, and will, can hold the Kremlin in check, he believes.

The relatively young Mr. Gorbachev is likely to be more thoughtful than his predecessors about the need to overcome economic and social stagnation and to reallocate resources from military to civilian sectors. Yet the Soviet system will endure for a long time yet: the Soviet people are matched only by the Chinese, Shevchenko thinks, in their ability to ``withstand centuries -- not decades -- of hardship and privation and yet persevere.''

So it is ``imperative'' for the West to ``seek reasonable and practical accommodation, even cooperation, when our interests are in alignment.''

This adds up to a more nuanced, sophisticated view than the strident anti-Sovietism more generally heard from those who have turned against the communist system, and it is put forward in this book in clear and well-organized prose.

To declare this reviewer's bias: I tend to agree with the thrust of Shevchenko's comments. The question is whether Shevchenko is a persuasive voice on wider grounds.

Defectors are only one source of information, and usually an imperfect one. They write about events well in the past. They are not above exaggerating the importance of what they did and what they knew in order to impress publishers, make more money, and attract attention.

Shevchenko himself was known to friends of mine at the United Nations in New York as a lover of fine consumer goods, a habitu'e of the stylish Manhattan store Bloomingdale's. It is believed in Washington that the friendship between his own first wife and the wife of veteran Soviet Foreign Minister Andrei Gromyko was more than helpful to his career. After his defection in April 1978, he had an unfortunate and highly publicized affair with a professional escort in New York.

On less personal, more professional grounds, Shevchenko clearly does not tell all in his book. The Central Intelligence Agency, which persuaded him to spy for the US as a double agent for two years before his actual defection, undoubtedly sanitized the manuscript. Shevchenko himself would hardly be human if he had not withheld information for subsequent books.

Yes, he had been UN undersecretary-general for political and security affairs (the highest-ranking Soviet member of the UN) for five years when he defected. But no, he did not have access to KGB or to military intelligence cables. His familiarity with diplomatic cable traffic gave him only a partial view of Soviet affairs.

So what are we to make of Shevchenko and his book?

In my view, and for all the reservations entered above, we are to make a good deal.

No other defector has been exposed to so much of the inner workings of Soviet diplomacy. No other has been on Gromyko's personal staff for several years. No other has traveled, talked, worked with Nikita Khrushchev and Leonid Brezhnev, or watched at close quarters men like the late Konstantin Chernenko and Yuri Andropov, or the current leader Gorbachev, if only briefly.

Yes, Shevchenko (like many Russians) has had his problems with alcohol. Yes, his private life bears scars. Yes, the Soviet system of sealing off separate compartments of government from each other limited his access.

But yes, too, he can give a firsthand account of the process, the machinery, the daily flavor and aroma of the ways Soviet foreign policy is made. This is a book less notable for its revelations than for the steady piling up of detail upon detail, for its atmospherics, for its almost offhand lines which add resonance and depth to our Western, nose-against-the-glass perspective.

Shevchenko, who now lives fairly openly with his second wife in Washington (he is still consulted at times by the State Department), had access to more policy information than any other defector except, perhaps, Col. Oleg Penkovsky, the military intelligence officer who revealed much about gaps in Soviet missile programs before the Cuban missile confrontation of 1962.

Shevchenko was no deprived or bitter man consumed with envy of his peers. He attended the best schools, was chosen by Gromyko to work on his personal staff for three years, sat in on Politburo meetings, lived in New York for years, and enjoyed the almost priceless benefits of the nomenklatura, the elite list of party-controlled jobs that hold the keys to layers of luxury and privilege.

The reasons he gives for defecting are familiar ones: disillusion with ideology and leadership hypocrisy, and a personal desire for freedom to write as he believed. Whatever the reasons, he provides a most useful look into Soviet foreign policymaking -- incomplete, of course, but more complete than we've had before.

I wish the book had a table of contents, proper chapter headings, and a more complete index. It seems clear that Shevchenko received considerable help with his English style, but no such help is acknowledged.

Clearly Shevchenko has not made up his mind on some points: on how important Soviet ideology is, for instance. Early in the book he disparages it as meaningless, but later it is clear that Lenin's view of the world as a ceaseless competition between Soviet communism and Western (now largely American) views does very much govern the Politburo's outlook and motives.

No matter. Read it, anyway.

Monitor London correspondent David K. Willis was based in Moscow from 1976 to 1980. His book ``Klass: How Russians Really Live'' will be out this summer.