THE VATICAN, as the saying goes, "thinks in centuries." Today, more than ever, this habit of mind may present drastic difficulties for a Church which must keep up with revolutions sexual, industrial and demographic, or today's flocks may outpace their shepherds' century-a-step crawl. The drama of a church falling behind the very people it is supposed to lead is the stuff of which great books are made. This, unfortunately, is not the book.

The first tip-off should come from the book's dust jacket, which features two Catholic clergymen praising the book's analysis. The Catholic Church, of course, hardly has a reputation for its graceful acceptance of criticism. Kind words from people who were still publishing an Index of acceptable books after World War II should perk a few suspicions. And as it turns out, Nichols is an avowedly sympathetic critic, very much intrigued by the faith, and himself married to a Catholic. He is on good terms with much of the Vatican, and indeed many of his anecdotes begin with the author sitting down to lunch with one bishop, or chatting in one Vatican hallway or another.

While such connections lend themselves well to personal sketches and amusing little stories, they create problems for Nichols in writing the sort of meaningful criticism to which he apparently aspires. He seems at times so busy avoiding stepping on any toes that he has trouble standing in one place very long, for fear that some official toe might appear underfoot.

For example, when he appears on the verge of declaring that the short-lived Pope John Paul I was really too shy and provincial ever to make a good pope, Nichols senses toes nearby and quickly hopes over to the conclusion that, "He scarcely survived a month, yet in that short time something momentous began to be felt...."

Nichols's analysis of world overpopulation is equally dizzying. He plants himself firmly by saying that the Vatican "gives far too little importance to population problems because of its teaching on birth control." But after some fancy footwork, a few pages later, he places overpopulation in his list of ten "principal causes of the decline of the human condition, about which the Catholic church has a perfect right to formulate views and let them be known as part of its claim to moral leadership." Nowhere does he imply that the Church should reconsider its approach.

When Nichols is not treading so nimbly, he is usually coming down squarely on the side of the Vatican on any controversial issue. Although, for example, the Vatican has refused to exchange diplomatic representatives with Israel, Nichols seems genuinely disappointed that Israel did not pay more attention to the Vatican's advice on how to supervise archeological shrines in Israel.

NOR IS NICHOLS particularly daring in expressing his own moral sentiments. His great statement on the rise of evil tends rather toward the tautological: "I make no claim to special sensitivity, but I am increasingly aware of a strong negative reaction inside me to people whom I feel, on first meeting, to be in some way negatively directed: to have too large a proportion of malice, or envy, or some other defect that disables their personalities." By necessity, the severest criticisms of the Vatican come not by the design of the author, but rather by the little absurdities that creep through the narrative. Nichols, for example, dryly sets forth the procedure for papal selection; he hardly mentions the irony of a ballot system so full of verifications and double checks that the cardinals seem less like spiritual colleagues than paranoid poll-watchers. Similarly, when Nichols launches into a description of the new location of Pope John Paul II's weekly audiences, he scarcely notices the irony of the fact that it was moved because crowds of penitent pilgrims "grew to the extent that scenes of violence broke out among ticket holders expecting to find a place."

Nichols couches it all in a style that is less than classically literary. His short, direct sentences are unmistakably journalistic. Indeed, he is not above beginning a sentence, "The reason I believe this is because..." And the logic in those sentences often falls even below their style. Nichols describes the papal selection process as "carried out by a hundred or so members of the most exclusive caste to gather anywhere in the world to elect an international personality." No doubt this is the most exclusive caste to gather to pick an international celebrity--and probably the only one.

But the real problem is simply that Nichols seems confused about his own goals. He wants to examine the many major issues facing the church, and how it must react, but he seems reluctant to provide the sort of tough devil's advocacy that such an investigation demands. The result is a book of pulled punches. The book's title comes from Stalin's famous reply, when told of the pope's likely opposition to a Soviet move: "How many divisions has the pope?" With a bit of clever wordplay, Nichols seems intent on making it mean not only the pope's military divisions, but his moral and spiritual divisions as well. Ironically, however, the divisions that the book succeeds in pointing out best are merely the author's own.