In 2013, Benedict unexpectedly resigned his papacy. He was the first Pope to do so in nearly 600 years. Afterward, he did not, as many expected, depart for an obscure Bavarian monastery. He stayed put, still accepting the title “His Holiness,” still wearing the pectoral cross of the Bishop of Rome, still publishing, still massaging his record, still meeting cardinals, still making statements, still involved. His very existence provides encouragement to conservative critics who want to undermine Francis’s reign.

Take Matteo Salvini, the populist deputy prime minister of Italy and head of the right-wing Lega Party. Salvini has called for immigration control and the barring of illegal immigrants, and deplores Francis’s exhortations to welcome all refugees. Salvini, who is friendly with Steve Bannon and the anti-Francis cardinal Raymond Burke, has been photographed holding a T-shirt emblazoned with the phrase IL MIO PAPA È BENEDETTO (“My Pope is Benedict”) and an image of a desperate-looking Francis.

Pope Francis and ambassadors to the Holy See at the Sistine Chapel, January 2017. Photograph from Vatican Pool/Getty Images.

The hostilities reached new heights last August, when Francis was visiting Ireland. Archbishop Carlo Maria Viganò, the formal papal nuncio to Washington, D.C., and a prominent conservative, issued a letter accusing Francis of turning a blind eye to sexual abuse and calling on him to resign as Pope. Viganò’s most serious charge is that Francis reversed sanctions that Benedict had placed on the American cardinal Theodore McCarrick, who has been accused of sexually abusing adult seminarians as well as an altar boy. (McCarrick denies this.) It took the Vatican six weeks to respond to the letter, though Viganò was sure Francis was talking about him when he asked Catholics to pray to Mary and St. Michael the Archangel to “protect the church from the devil, who is always looking to divide us from God and from one another.” By the time the Vatican issued a statement condemning Viganò’s allegations as “false,” “blasphemous,” “abhorrent,” and politically motivated, Francis’s popularity in the U.S. had dropped to 51 percent, 19 points below where it had been in January 2017.

It’s hard to blame Francis’s defenders for taking a skeptical view of conservative outrage over the papacy’s handling of sexual abuse. Francis has gone much further than John Paul II and Benedict ever did to acknowledge that the Catholic Church bears shameful responsibility for the sexual-abuse scandals that have erupted around the world in recent decades. Still, Francis’s instinct for empathy—and, perhaps, his hatred of gossip—has led him to make a series of unforced errors. In August, a Pennyslvania grand jury reported evidence of a widespread cover-up of sexual abuse by Church leaders, including Cardinal Donald Wuerl, the Archbishop of Washington, D.C. Francis responded by accepting Wuerl’s resignation, yes, but also praising Wuerl for his “nobility” and asking him to continue running his archdiocese until a replacement could be found. Earlier this year, Francis had rushed to the defense of Chilean bishops accused of covering up sexual abuse, only to reverse himself after a 2,300-page report he had commissioned painted an unmistakable picture of misconduct.

Disentangling this legacy of shame would be challenging enough for a Pope who wasn’t looking over his shoulder at a predecessor.

To what can this two-Pope circumstance be compared? We are in the realms of archetypes and myth. Think King Lear, who gave all yet stayed to control, disastrously, or Hamlet’s Ghost. The mere presence of a former Pope has been enough to test the mettle and independence of Francis from day one.

Would the jolly John XXIII have initiated the reforming Second Vatican Council had Pius XII, his autocratic predecessor, been watching lugubriously from a neighboring window? And would John Paul II have shaken the rotting tree of the Soviet Union had the anguished, hesitant Paul VI, who had contemplated a Vatican accord with Moscow, been lurking at his elbow? Whatever the direction of the papacy, left or right, for better or for worse, it’s the unique, exclusive primacy of one Pope at a time that lends supreme authority and power to his office. Loyalty through thick and thin to the single living Supreme Pontiff is the open secret of Catholic unity.