VATICAN CITY — Four years ago, Pope John Paul II was named a saint, a step that seemingly secured the legacy of one of the 20th century’s towering figures.

Instead, his papacy has come under an increasingly sharp and unsaintly critique, with some faithful saying that his muted response during the early years of the sexual abuse crisis continues to haunt the Roman Catholic Church.

Debate about the actions of a papal saint would have been highly improbable in an earlier era of Catholicism, when popes were only rarely given the highest honor in the faith.

But recent years have seen a rapid surge in papal saint-making, with the Vatican canonizing its former leaders in massive ceremonies in St. Peter’s Square — sometimes before history has rendered a final judgment on their papacies.

When Paul VI is canonized Sunday, along with martyred Salvadoran Archbishop Óscar Romero, he will be the third pope to be canonized in four years.

Paul VI’s successor, John Paul I, who held the position for just 33 days until his death, is also in the pipeline, meaning the Vatican office responsible for saints is looking into his case.

Though canonization is meant to reflect a person’s virtue — not his or her place in the history books — some outsiders say the church has placed itself in an awkward position by turning sainthood into a near-default for modern popes. In a modern record, John Paul II was canonized nine years after his death in 2005.

The church is now dealing with a global wave of sexual abuse crises, challenging its standing, and details continue to emerge about how the institution dealt with the issue in earlier decades.

Some of the cases that have erupted this year into public view have raised questions about inattention to abuse during the papacy of John Paul II.

“The question becomes: Why the rush?” said Christopher Bellitto, a history professor at Kean University, who suggested instead a mandatory 50- or 75-year waiting period on canonization after a pope’s death. “Papacies are complicated things, and we learn more about them after the pope has died.”

The process of minting saints is an elaborate one, involving a dedicated Vatican office that vets the candidate’s credentials, as well as doctors and other experts who look for evidence of otherwise inexplicable “miracles,” often involving cured ailments and diseases. Most candidates require one miracle before beatification and another miracle for the final step of sainthood. But always, the current pope has the authority to hasten the process or lower the bar for the number of miracles.

Saints are not beyond reproach. But controversy can indeed keep popes from canonization.

One modern pope who isn’t yet a saint, Pius XII, died in 1958 but is the subject of ongoing controversy for his policies during World War II, including whether he did enough to speak out against the rise of Nazi Germany and the Holocaust.

Cardinal Angelo Becciu, the new head of the Vatican’s saint-making office, said this past week that Pius’s case “has not progressed.”

“The most important judgment is the one on the sanctity of life,” said Monsignor Guido Mazzotta, a Vatican judge who assessed the case for Paul VI, the pontiff who reigned until 1978 and is remembered, in part, both for leading the church reforms known as Vatican II and for his encyclical reasserting Catholic opposition to birth control.

The saintly Catholic roster has about 10,000 members — including roughly one-third of the religion’s 266 popes.

Almost every pope during the first 500 years of the church was canonized. But then, just three of the 66 pontiffs between 1294 and 1914 received the honor, according to data compiled by Bellitto.

Over the past decade, the trend of papal saint-making has drastically re-accelerated — perhaps a recognition of how post-World War II popes have taken on an expanded role as globe-trotting symbols of the faith.

In that sense, John Paul II, who reigned for more than 26 years until his death in 2005, was the ultimate example. He visited more than 120 countries and helped to galvanize a global fight against communism. On the day of his funeral, mourners were already chanting, “Santo Subito,” or “Saint Now.”

John Paul II’s handling of sex abuse allegations was controversial even during his lifetime. But some experts say that the repercussions of his approach are becoming more evident after his death, even to the point of changing his legacy.

Though Vatican watchers debate how informed John Paul II had been about some abusers, they say he dealt with the issue with a Cold Warrior’s fortress mentality, opting for secrecy in handling cases and tending to view individual priests as the problem — paying little attention to the hierarchy that protected them. The question of oversight for bishops and cardinals has since turned into a central issue in multiple scandals.

“He has been dead for 13 years, and the issue of the accountability of bishops — that was the ticking time bomb that has now gone off,” said David Gibson, director of Fordham University’s Center on Religion and Culture. “John Paul and his legacy is at the center of the blast zone.”

In part, the spotlight has returned to John Paul II because of Theodore McCarrick, who resigned from the College of Cardinals this summer amid allegations about sexual misconduct.

McCarrick’s historic downfall has prompted questions about how he was able to ascend within the faith despite warnings — sent to the Vatican as early as 2000 — about his behavior.

Francis, facing accusations that he knew about McCarrick’s alleged abuse of young men, has pledged to open the Vatican archives to investigate. But the Vatican said last week in a statement that “it may emerge that choices were taken that would not be consonant with a contemporary approach to such issues.” McCarrick was promoted to archbishop of Washington and cardinal under John Paul II.

John Paul’s many defenders note that his health was failing in the last years of his life and that he was surrounded by key lieutenants who may have handled some decisions for him.

“Karol Wojtyla wasn’t a man who would stop when faced with real problems when they were presented to him,” said Wlodzimierz Redzioch, the author of a book about John Paul II, referring to the Polish-born pope by his birth name. “Had anyone presented this issue in all of its gravity, he would surely have tackled it.”

Monsignor Slawomir Oder, who presented John Paul II’s case for sainthood inside the Vatican, said that “all of the verifications that have been conducted confirm the integrity of the saint’s behavior.”

“This has been ascertained without a doubt,” Oder said.