John Cornwell, famous for implicating the Catholic Church in the Holocaust with 1995’s “Hitler’s Pope,” has now turned on the current Pope with “The Pontiff in Winter: Triumph and conflict in the reign of John Paul II” (Doubleday, 352 pages, $24.95). On the surface, “The Pontiff in Winter” takes issue with some reactionary reforms of an overly conservative pope. At its heart, it assails ancient Catholic teachings and the entire institution of the papacy.

In some sense, “The Pontiff in Winter” is the logical follow-up to “Hitler’s Pope.” While Mr. Cornwell charged Pius XII with outrageous crimes; his indictment of John Paul II is hardly as damning. Without a single footnote to substantiate his claims and in many cases lacking specific examples, Mr. Cornwell’s latest book looks less like a polemic and more like a half-hearted effort to cash in on his reputation as a disaffected Catholic writer. Even those who found the previous book compelling or controversial should see this books as the lame attack it is.

Mr. Cornwell’s is an old trick: Pretend to criticize some particular sect or trend within the Church, while in fact trying to undermine the entire Church. “His hard line on all forms of contraception … has alienated generations of the faithful,” Mr. Cornwell complains of John Paul II. He has decried “those Catholics who are divorced and remarried without annulment . . . or who live in unmarried partnerships or in homosexual relations.” In short, anywhere Catholic teaching conflicts with contemporary Western sexual mores, Mr. Cornwell finds fault with the current Pope.

Pervading the book is the word “pluralism,” a concept the author says the Pope rejects. “At a time when fundamentalist religions are in antagonistic confrontation with the West,” writes Mr. Cornwell, “his most tragic failure has been his refusal to acknowledge the potential for discovering within Christianity a basis for pluralist societies.” Exhibit A is the Vatican declaration Dominus Jesus, which claims that other religions are “deficient” in their relation to the savior and their apprehension of the truth insofar as they reject Catholic teachings.

In plain language, the declaration, signed by Joseph Cardinal Ratzinger, was saying: “to the extent that you disagree with us, we think you’re wrong.” For Mr. Cornwell, this is proof enough that this Pope is close-minded and intolerant. But in decrying it, Mr. Cornwell is rejecting either all Catholic teaching, or the law of noncontradiction.

In such sections, Mr. Cornwell’s footing is less than sure. But others are more egregious still. As he attempts to get inside the mind of John Paul II, Mr. Cornwell shows a tendency to exaggerate, extrapolate, and simply make things up.

While not explicitly recycling the same charges he made against Pius XII, Mr. Cornwell writes, “It is uncertain to this day just what Karol Wojtyla did and did not do to help Jewish victims during the war.” He insinuates that an early mentor’s celibacy was due to “an occasional hint of gay ostentation” and accuses the founder of Opus Dei, whose work John Paul II endorsed, of having close ties with the fascist Spanish dictator General Francisco Franco.

Perhaps Mr. Cornwell’s worst moment comes in a chapter called “Close Encounters,” with the stories of what John Paul II’s critics inferred about the pontiff after meeting with him. “I caught the sudden impression of the Niagara of sycophancy, persuasion, and petition that poured into that ear day by day,” Mr. Cornwell writes about the tilt of the pontiff’s head.

The clincher comes in citations from the novelist Graham Greene, in which John Paul hands out rich chocolates as communion wafers and presumes to canonize Jesus Christ. Meant to capture the arrogance and opulence of John Paul II, these passage are from Greene’s dreams – still, Mr. Cornwell somehow finds them relevant and telling.

At one particularly disingenuous moment, Mr. Cornwell feigns sympathy for John Paul, but only to make a deeper stab at the church. “Whatever the character of the man who becomes pope,” Mr. Cornwell writes, “the papal role, in time, begins to take over the human being, the personality of the individual elected to the strangest, most impossible and isolating job on earth.” He continues: “We will never know the solitude, the psychological fragmentation, the inner sufferings that have afflicted John Paul in consequence of his papal office. But there are clues.”

Mr. Cornwell’s project is not just to show that this man is “autocratic” and reactionary, but that these flaws are inevitable whenever a human is put in such a position – in other words, to question whether the papacy is good for the Church.

Mr. Carney is a writer living in Washington, D.C.