In 1979, almost a year into the papacy of John Paul II, a novel called The Vicar of Christ spent 13 weeks on the New York Times best-seller list. The work of a Princeton legal scholar, Walter F. Murphy, it featured an unlikely papal candidate named Declan Walsh—first a war hero, then a United States Supreme Court justice, and then (after an affair and his wife’s untimely death) a monk—who is summoned to the throne of Saint Peter by a deadlocked, desperate conclave.

Once elevated, Walsh takes the name Francesco—that is, Francis—and sets about using the office in extraordinary ways. He launches a global crusade against hunger, staffed by Catholic youth and funded by the sale of Vatican treasures. He intervenes repeatedly in world conflicts, at one point flying into Tel Aviv during an Arab bombing campaign. He lays plans to gradually reverse the Church’s teachings on contraception and clerical celibacy, and banishes conservative cardinals to monastic life when they plot against him. He flirts with the Arian heresy, which doubted Jesus’s full divinity, and he embraces Quaker-style religious pacifism, arguing that just-war theory is out of date in an age of nuclear arms and total war. (This last move eventually gets him assassinated, probably by one of the governments threatened by his quest for peace.)

Murphy’s book is mostly forgotten, but his hook, the idea of a progressive pope who sets out to bring sweeping change to Catholicism, has endured in the cultural imagination. The priest-novelist Andrew M. Greeley’s 1996 potboiler White Smoke, for instance, culminates in the election of a modernizing Spanish cardinal, whose conservative opponents are undone by the wily politicking of two Irish American prelates. Two years ago, Showtime shot a pilot for a series called The Vatican, in which Kyle Chandler (a k a Coach Taylor from Friday Night Lights) played a rising-star New York cardinal with progressive views—only to spike the show, perhaps feeling overtaken by events, 10 months after Pope Benedict XVI unexpectedly resigned.

The possibility of a revolutionary pope isn’t one that most Vatican-watchers have taken seriously, and not only because a college of cardinals with members appointed by John Paul and Benedict seemed unlikely to elevate a true wild card to the office. The reality is that popes are rarely the great protagonists of Catholic dramas. They are circumscribed by tradition and hemmed in by bureaucracy, and on vexing issues Rome tends to move last, after arguments have been thrashed out for generations.

Yet now we have a Pope Francesco in the flesh, and elements of Murphy’s vision have come to pass, or so it seems: the attention-grabbing breaks with papal protocol, the interventions in global politics, the reopening of moral issues that his predecessors had deemed settled, and the blend of public humility and skillful exploitation—including the cashiering of opponents—of the papal office and its powers.

The Church is not yet in the grip of a revolution. The limits, theological and practical, on papal power are still present, and the man who was Jorge Bergoglio has not done anything that explicitly puts them to the test. But his moves and choices (and the media coverage thereof) have generated a revolutionary atmosphere around Catholicism. For the moment, at least, there is a sense that a new springtime has arrived for the Church’s progressives. And among some conservative Catholics, there is a feeling of uncertainty absent since the often-chaotic aftermath of the Second Vatican Council, in the 1960s and ’70s.

That unease has coexisted with a tendency to deny that anything has really changed since the former cardinal and archbishop of Buenos Aires became pope. From the first unscripted shocker—his “Who am I to judge?” in response to a reporter’s question about gay priests—many conservative Catholics have argued that the press is seeing what it wants to see in the new pontiff. Taking his comments and gestures out of context, reporters are imposing a Declan Walsh frame on a reality in which continuity is still the order of the day.

The conservative observers are often right. Some of Francis’s gestures mirror moves his predecessors made to less fanfare or acclaim. Some of his forays into world affairs, like the opening to Cuba, build on Vatican diplomatic efforts begun before his time. Some of his leftward-tilting public statements—the critiques of global capitalism, the stress on environmental stewardship—are in step with the rhetoric of both John Paul and Benedict. Some of his headline-grabbing comments (on the compatibility of Catholic doctrine and evolutionary theory, say) get attention only because certain reporters have no real clue about what Catholicism teaches; others (like his alleged promise that pets go to heaven) because journalists will believe any story that fits the “maverick pope” narrative.

Yet the media are not deceived in thinking that Francis differs from his predecessors in substance as well as style. He may not be a liberal Catholic as the term is understood in an American or European context, but he has a different set of priorities than the previous two popes did. He reads the times differently, and elements of his agenda are clearly in tune with what many progressive Catholics (and progressives, period) in the West have long hoped for from the Church.

The exact details of that agenda can sometimes be difficult to discern. Phrases like master of ambiguity circulate among admirers and critics alike. But there are now a number of biographies of Francis/Bergoglio in English, and three of them, read together, give a provisional sense of where this pope is coming from. They also suggest why his pontificate, without being as deliberately revolutionary as the reigns of the liberal popes of fiction, might have dramatic consequences for the Church.

The arc of Bergoglio’s life and career follows a literary script: youthful success, defeat and exile, unexpected vindication and ascent. Each of his three biographers approaches the story in a different way. Elisabetta Piqué, a correspondent for the Argentine newspaper La Nación, has written an intensely personal work (Bergoglio baptized her two children); her Pope Francis: Life and Revolution draws richly on interviews with Argentinians touched by Bergoglio’s pastoral work. The Great Reformer: Francis and the Making of a Radical Pope, by the British Catholic journalist Austen Ivereigh, has the widest angle and the most depth, taking in Argentina’s distinctive history as well as the particular trajectory of its now most famous son. In Pope Francis: Untying the Knots, Paul Vallely, another British Catholic writer on religion, develops a distinctive interpretation of his subject.

But the basic narrative is there in all three treatments. The descendant of Italian immigrants to Argentina, devout from an early age and committed to the priesthood after a teenage epiphany, Bergoglio entered the Jesuit order in 1958, just four years before the Second Vatican Council opened in Rome. His training was long (Jesuits spend more than a decade “in formation”) and initially old-fashioned in its rigors; the order in Argentina devoted a great deal of its work to educating the national elite. But by the time he took his final vow and became a Jesuit in full, in 1973, the reforms of the Council and the turbulence that followed had dramatically changed his order, and divided it.

Many of Bergoglio’s fellow Jesuits believed they had a postconciliar mandate to make the pursuit of social justice the order’s organizing mission. In Latin America, the emerging Big Idea for what this meant was liberation theology, which promoted a synthesis between Gospel faith and Marxist-flavored political activism. Argentina’s provincial, the head of the country’s Jesuits, Ricardo O’Farrell, offered encouragement to these ideas. He backed priests who essentially wanted to live as political organizers among Argentina’s poor. He also supported a syllabus rewrite that was “heavy on sociology and Hegelian dialectics,” as Ivereigh describes it, and lighter on traditional Catholic elements.

But O’Farrell soon found himself dealing with a crisis: the number of men entering the order plummeted, and more-conservative Jesuits openly revolted. In the summer of 1973, he stepped aside, and at just 36, Bergoglio was elevated in his place. In many ways he made a success of things. The order’s numbers rebounded, and he won many admirers among the priests formed under his leadership. But he made enemies as well, most of them on the order’s theological and political left. Radical priests felt that their revolution had been betrayed, and a coterie of Jesuit academics fretted that Bergoglio’s program for Jesuits in training—which restored traditional elements abandoned by O’Farrell—was too reactionary, too pre–Vatican II. Ivereigh quotes one critic marveling that Bergoglio encouraged students to

go to the chapel at night and touch images! This was something the poor did, the people of the pueblo, something that the Society of Jesus worldwide just doesn’t do. I mean, touching images … What is that?

His leadership also coincided with the 1976 military coup and the “Dirty War,” during which left-wing Jesuits were particular targets for the junta’s thugs. Bergoglio was accused of complicity in the arrest and torture of two priests, a charge that Ivereigh and Piqué think is baseless; Vallely hedges, but seems to mostly concur. Indeed, all three biographers make clear that Bergoglio labored tirelessly behind the scenes to save people (not only priests) in danger of joining the ranks of the “disappeared.”

But he did not attack the Dirty War publicly, and the Jesuits under his leadership kept a low political profile as well. The entire Argentine Church was a compromised force during the junta’s rule, and Bergoglio probably couldn’t have played the kind of role that, say, the soon-to-be-beatified archbishop Oscar Romero played in El Salvador. But some in the order blamed his conservatism, as they saw it, for the absence of a clear Jesuit witness against the junta’s crimes.

Eventually these critics gained the upper hand. Not long after Bergoglio’s term ended in 1979, his policies were altered or reversed. Just over a decade later, following a period in which the Argentine Jesuits were divided into pro- and anti-Bergoglio camps, he was exiled from the leadership, sent to a Jesuit residence in the mountain town of Córdoba, and essentially left to rot.

That exile lasted almost two years, and ended when John Paul II’s choice for the archbishop of Buenos Aires, Antonio Quarracino, reached out and picked Bergoglio to serve as one of his auxiliaries in 1992. The rescue made everything that followed possible, but it also completed the former provincial’s break with his own order. Ivereigh notes that over the next 20 years, during which he took many trips to the Vatican, Bergoglio never so much as set foot in the Jesuit headquarters in Rome.

Told this way—conservative Jesuit fights post–Vatican II radicalization, finds himself shunned by left-wing confreres, gets rescued by a John Paul appointee—the story of Francis’s rise and fall and rise sounds for all the world like The Making of a Conservative Pope. And indeed, a number of Catholic writers greeted Bergoglio’s election—some optimistically, some despairingly—with exactly that interpretation of his past’s likely impact on his papacy. But it seems fair to say that this interpretation was mistaken. So how, exactly, did the man who fought bitterly with left-wing Jesuits in the 1970s become the darling of progressive Catholics in the 2010s?

Piqué’s biography doesn’t even attempt to explain this seeming paradox. She blurs the tensions by treating Bergoglio’s 1970s-era critics dismissively—without really digging into the theological and political roots of the disputes—and then portraying Bergoglio the archbishop as basically progressive in his orientation. After succeeding Quarracino, she writes, he fought with “right-wing adversaries in the Roman Curia,” publicly showed annoyance at “obsessive strictness” on sexual ethics, and so on.

Vallely has a more creative argument. He suggests that Francis was essentially a pre–Vatican II traditionalist as provincial, and then, in exile, experienced a kind of theological and political conversion to his critics’ point of view. This is a fascinating idea, but perhaps too psychologically pat, and Vallely’s documentary evidence is interesting but thin. He makes much, for instance, of the older Bergoglio’s tendency to retrospectively criticize the too-hasty or overly authoritarian decision making of his earlier years. But much of this self-criticism seems more about style than about religious substance. And Vallely (like his sources) is rather too fond of false dichotomies: it’s supposed to be surprising, a sign of some radical interior change, that a theological conservative could be pastoral or want to spend time among the poor.

Bergoglio’s thinking clearly evolved. But the more plausible explanation for what’s going on emerges out of Ivereigh’s biography, which proposes a general continuity between the young provincial of the 1970s and the pope of today. To begin with, Ivereigh stresses that the younger Bergoglio was never a real traditionalist, never an enemy of Vatican II, never a foe of renewal or reform. Instead, he was trying to heed the warning of Yves Congar, the great mid-century Catholic theologian, that “true reform” must always be safeguarded from “false” alternatives. Bergoglio’s battles with radicals and liberals in his own order shouldn’t be interpreted as a case of the Catholic right resisting change. They should be understood as an attempt to steer a moderate course, to discern which changes are necessary and fruitful, and to reject the errors of both extremes.

This perspective undergirds Ivereigh’s larger argument that—the attention-grabbing “radical pope” language in his subtitle notwithstanding—there’s actually a greater consistency of views among Francis, Benedict, and John Paul than some press caricatures would suggest. Both of Francis’s predecessors were also men of Vatican II, liberals in the context of the Council’s debates who tried to rein in radical interpretations of its reforms and emphasize the continuity between the Church before and after. Like Francis, both were defenders of popular Catholic piety and mysticism—what Benedict, as Cardinal Ratzinger, called “the faith of the little ones”—against the condescension of certain progressive theologians. And both, like him, rejected fusions of Christianity and Marxism while offering at best a cheer and a half for capitalism.

Yet several crucial issues—some raised explicitly by Ivereigh, some implicit in all three biographies—set Francis’s background and worldview apart. They help explain why his pontificate looks much more friendly to progressive strands within Catholicism than anyone expected from the successor to the previous two popes.

First, Jorge Bergoglio had a very different experience of globalization than Karol Wojtyła (who would become Pope John Paul II) and Joseph Ratzinger did in Europe, one shaped by disappointments particular to his country. For most of his life, his native Argentina was an economic loser, persistently underperforming and corruption-wracked. During the 1980s, inequality and the poverty rate increased in tandem; in the late ’90s and early 2000s, while Bergoglio was archbishop, Argentina endured a downturn and a depression. Where his predecessors’ skepticism of capitalism and consumerism was mainly intellectual and theoretical, for Bergoglio the critique became something more visceral and personal.

Second, in the course of his political experience in Argentina, he encountered very different balances of power—between the left and the right, between Church and state, and within global Catholicism—than either of the previous two popes confronted. As much as Bergoglio clashed with Marxist-influenced Jesuits, the Marxists in Argentina weren’t running the state (as they were in John Paul’s Poland, and in the eastern bloc of Benedict’s native Germany). They were being murdered by it. Likewise, the fact that the Church in Argentina was compromised during the Dirty War had theological implications: it meant that for Bergoglio, more-intense forms of traditionalist Catholicism were associated with fascism in a very specific, immediate way. And coming from the Church’s geographical periphery himself, Bergoglio had reasons to sympathize with the progressive argument that John Paul had centralized too much power in the Vatican, and that local churches needed more freedom to evolve.

Third, while highly intellectual in his own distinctive way, Francis is clearly a less systematic thinker than either of his predecessors, and especially than the academic-minded Benedict. Whereas the previous pope defended popular piety against liberal critiques, Francis embodies a certain style of populist Catholicism—one that’s suspicious of overly academic faith in any form. He seems to have an affinity for the kind of Catholic culture in which Mass attendance might be spotty but the local saint’s processions are packed—a style of faith that’s fervent and supernaturalist but not particularly doctrinal. He also remains a Jesuit-formed leader, and Jesuits have traditionally combined missionary zeal with a certain conscious flexibility about doctrinal details that might impede their proselytizing work. This has often made them controversial among other missionary orders, as in the famous debate over the efforts of Matteo Ricci. A Jesuit in China during the late 16th and early 17th centuries, Ricci was attacked for incorporating Chinese concepts into his preaching and permitting converts to continue to venerate their ancestors. That Ricci is currently on the path to canonization, and his critics are mostly forgotten, says something important about the value of Jesuit envelope-pushing within the Church. But it also says something important that Catholicism has never before had a Jesuit pope.

Finally, Francis has a different base of support—and thus a different set of debts to pay, perhaps—within the Catholic hierarchy than the popes who preceded him had. He became a papal candidate at the 2005 conclave, and was elected pope eight years later, thanks to efforts made on his behalf by a small group of European cardinals, including Godfried Danneels of Belgium, Walter Kasper of Germany, England’s Cormac Murphy-O’Connor, and the late Carlo Maria Martini, himself a Jesuit and the former archbishop of Milan. In the John Paul era, all four men were among the most theologically liberal cardinals; Martini was regarded wistfully as a kind of might-have-been progressive pope.

Both Ivereigh (a former adviser to Murphy-O’Connor) and Vallely leave little doubt as to this group’s importance. What is in doubt is how Bergoglio, who reportedly urged his supporters to vote for Ratzinger in 2005 rather than prolong the vote, felt about their efforts in either conclave, and how he feels about them now. Clearly the liberal cardinals fastened onto him as a candidate because they saw him as theologically closer to the center of the conclave and more doctrinally reliable than any of their group; clearly his support within the 2013 conclave extended well beyond just the liberal faction. At the same time, it is striking that the men who arguably did the most to make Bergoglio pontiff were among the cardinals most in opposition to the previous two popes.

These distinctive features of his background have helped define Francis’s agenda for the Church. The areas where he has the strongest mandate lie in governance: reforming the Vatican bureaucracy, purging corruption from the Curia, and reorienting the Church’s leadership toward the global South. These projects are natural extensions of his past experience, as are their rhetorical accompaniments—the public scoldings of worldly and careerist clergy, and the vision of a Church in which the “peripheries” (Africa, Latin America, Asia) bring renewal to the center.

So too with what looks like the broadest theme of his pontificate: his constant stress on economic issues, the Church’s social teachings, and the plight of the unemployed, the immigrant, the poor. The content here may not be different from previous papal statements on these subjects, but Francis returns to these issues much more often. His sharp, prophetic tone—the recurring references to the “throwaway culture” of modern capitalism, the condemnation of “an economy [that] kills”—seems intended to grab attention, to spotlight these issues, and to shatter the press’s image of a Church exclusively interested in sexual morality.

In this sense and others, Francis may indeed see his papacy as a kind of moderate corrective to the previous two. Rather than conceiving of himself primarily as a custodian of Catholic truth against relativizing trends, he seems to be trying to occupy a carefully balanced center between two equally dangerous poles. At one extreme are “the ‘do-gooders’ ” and “the so-called ‘progressives and liberals,’ ” as he put it in his closing remarks to last fall’s synod on the family. At the other extreme, to be equally condemned, are “the zealous” and “the scrupulous” and “the so-called—today—‘traditionalists.’ ”

To further that balancing act, his appointments, while hardly uniform, have filled the higher ranks of bishops and cardinals not only with more non-Europeans but with more men from the Church’s progressive wing. (The most prominent example is Blase J. Cupich, the new archbishop of Chicago, who was plucked from a minor diocese to run one of America’s most important sees.) Meanwhile Francis has shown explicit disfavor, not so much toward mainstream-conservative clerics, but toward those explicitly associated with traditionalism and the Latin Mass. Cardinal Raymond L. Burke, a Benedict appointee demoted to a mostly ceremonial position, is the famous case, but traditionalist-leaning bishops and religious orders have felt a chill wind at times as well.

Amid these moves, conservative Catholics have consoled themselves by noting that Francis is not at all like the left-wing Jesuits he feuded with in the 1970s. As he certainly is not: His economic vision offers a general critique of greed and indifference, rather than a specific social-democratic program, and there is nothing secularized about his style. He is devotional in his piety, supernatural and sometimes apocalyptic in his themes (complete with frequent mentions of the devil), and emphatic about the importance of the sacraments and saints. And he has stated clearly that he has neither the intention nor the capacity to alter the Church’s teachings on such issues as abortion and same-sex marriage.

All of this makes it imaginable that Francis could succeed in his balancing act. So long as doctrine doesn’t seem to be in question, a papal agenda focused on ending corruption in the Vatican and emphasizing a commitment to the global poor could successfully straddle some of the Church’s internal divides—not least because those divides aren’t always as binary as the language of “left and right” suggests. Many theological conservatives in the developing world are natural economic populists, and they’re perfectly happy with the way this pope talks about globalization and the free market. The allergy to some of his rhetoric is mostly confined to the American right, and even there it’s largely an elite-level phenomenon; Francis’s approval rating in the United States among conservative Catholics is about as high—that is, very high—as it is among Catholics who identify as moderate or liberal. And at least some in the latter groups mostly want the Church to de-emphasize the culture war rather than change specific teachings, so Francis’s rhetorical shifts may be enough to satisfy them.

But there are times when Francis himself seems to desire something more than just a change in emphasis. Even as he has officially reaffirmed Church teachings on sex and marriage, he has shown a persistent impatience—populist, Jesuit, or both—with the obstacles these teachings present to bringing some lapsed Catholics back to the Church. His frustration has emerged most clearly on the issue of divorce and remarriage: he has repeatedly shown what seems to be tacit support for the idea, long endorsed by Walter Kasper and other liberal cardinals, to allow Catholics in a second marriage to receive Communion even if their first marriage is still considered valid—that is, even if they are living in what the Church considers an adulterous relationship.

The argument, from Kasper and others, is that this would be strictly a pastoral change, a gesture of welcome and forgiveness rather than an endorsement of the second union, and so it wouldn’t alter the Church’s formal teaching on the indissolubility of marriage. The possible implication is that the post-sexual-revolution landscape is now as culturally foreign to the Church as China was in the age of Matteo Ricci, and that some cultural accommodation is needed before missionary work can thrive.

The problem for Francis is that Kasper’s argument is not particularly persuasive. Describing Communion for the remarried as merely a pastoral change ignores its inevitable doctrinal implications. If people who are living as adulterers can receive Communion, if the Church can recognize their state of life as nonideal but somehow tolerable, then either the Church’s sacramental theology or its definition of sin has been effectively rewritten. And the ramifications of such a change are potentially sweeping. If ongoing adultery is forgivable, then why not other forms of loving, long-standing sexual commitment? Not only same-sex couples but cohabiting straight couples and even polygamous families (a particular concern among African cardinals) could make a plausible case that they deserve the same pastoral exception, rendering the very idea of objective sexual sin anachronistic in one swift march.

This, then, is the place where Francis’s quest for balance could, through his own initiative, ultimately fall apart, bringing the very culture war he’s downplayed back to center stage. And it’s the place where his pontificate could become genuinely revolutionary. His other moves are changing the Church, but in gradual and reversible ways, leaving lines of conflict blurry and tensions bridgeable. But altering a teaching on sex and marriage that the Church has spent centuries insisting it simply cannot alter—a teaching on a question addressed directly (as, say, homosexuality is not) by Jesus himself—is a very different thing. It would suggest to the world, and to many Catholics, that Catholicism was formally capitulating to the sexual revolution. It would grant the Church’s progressives reasonable grounds for demanding room for further experiments. And it would make it impossible for many conservatives, lay and clerical, to avoid some kind of public opposition to the pope.

Such a development probably would not produce an immediate crisis or schism. But it would put the Church on the kind of trajectory that the Anglican Communion and other Protestant denominations have traced on these issues, and would make some eventual division much more likely. As pastoral experiments proliferated, geographical and cultural differences would matter more and more, and official Catholic teaching would effectively vary from country to country, diocese to diocese, in a more explicit way than it does today. (Already, the German bishops are telegraphing their intention to move ahead with a Kasper-like approach no matter what happens in Rome.) Open clashes within the hierarchy would become commonplace. Criticisms of the pope would become normal among the self-consciously orthodox, and the stakes would get higher with every subsequent papal election and intervention.

None of this would be exactly new: Catholic Christianity has never been monolithic, and similar divisions have opened up across the past 2,000 years. But those examples are not particularly encouraging, given that many major theological disputes have led, as you would expect, to major schisms, from the early splits with the Copts and Monophysites and Nestorians, to the separation from the Eastern Church, to the late-medieval Great Schism, and of course to the Protestant Reformation.

Perhaps the debates of the sexual revolution will look less significant in hindsight than controversies over the nature of Christ’s divinity or Reformation-era arguments about papal authority and the sacraments. But from the beginning, sexual ethics have been closer to the heart of Christianity and Christian life than many theological progressives now assume. Not for nothing did Philip Rieff describe ideals like monogamy and chastity as part of “the consensual matrix of Christian culture.” It’s not really surprising that in Protestant churches, these debates have often threatened or produced schism.

Which raises an important question: Is this what liberal Catholics want?

The answer, in my experience, is no. Most liberal Catholics would simply dismiss the argument I’ve just made. Some don’t see any reason the Church can’t enact one or two changes on sexual ethics while holding the line on other fronts; they think conservatives are exaggerating the extent to which the Church’s view of human sexuality is, like Jesus’s robe, a seamless garment. Others sincerely think that a shift like the one Cardinal Kasper is proposing really does amount to merely a pastoral tweak (like the post–Vatican II disappearance of meatless Fridays), and conservatives will grumble and then quickly learn to live with it.

More broadly, there’s an assumption that a distinction between practice and doctrine is sustainable, or at least sustainable over the decades or centuries required for conservative opposition to diminish. Indeed, many liberal Catholics would say that’s how the Church always changes. A teaching or an idea (the prohibition against usury, say, or the theological speculation that unbaptized infants who die go to Limbo) gradually becomes vestigial: Catholics ignore it and churchmen stop talking about it, and then eventually the hierarchy comes up with some official-sounding explanation (one that starts, “As the Church has always taught …”) for why it’s no longer really in force. The rest of Catholic teaching holds together just fine during this transition; there’s no danger of a Jenga effect, no thread-pulling that ends up unraveling the whole.

This view is widespread without always being made explicit. Sometimes it gets a full airing, though: in his new book, The Future of the Catholic Church With Pope Francis (in which the pontiff himself appears mostly in extremely selective quotation), the longtime papal critic Garry Wills offers a vision of the Catholic future in which the Church’s understanding of natural law, its opposition to abortion, and even the sacrament of confession are all destined for the same fate as the Latin Mass. (Wills already dispensed with the priesthood itself in Why Priests? A Failed Tradition, so disposing of a sacrament is relatively easy work.)

His view of Catholic history is ruthlessly consistent. The “development of dogma” really just means that doctrines come and go at history’s whim, and no idea or institution—save some kind of belief in Jesus’s divinity, presumably—is necessarily essential. Instead there’s just one damn thing after another, and if the Church teaches one thing in one age, reversing itself in the next is no big deal. Here his book boldly repurposes the views of G. K. Chesterton, who pointed out how impressively the Church shook itself free of the failing Roman empire, the dying medieval world, and eventually the ancien régime. To Chesterton, this proved the faith’s resilience and ultimately its capital‑T Truth. To Wills, it proves that the Church can just change the faith as it sees fit to suit a changing world.

Wills is an outlier among liberal Catholics, most of whom tend to be more modest and gradualist, and less inclined to take premises to their extreme. But most progressives share his basic conviction that conservative resistance on just about any doctrinal issue can eventually be overcome, and that Catholicism will always somehow remain Catholicism no matter how many once-essential-seeming things are altered or abandoned.

In the age of Francis, this progressive faith seems to rest on two assumptions. The first is that the changes conservatives are resisting are, in fact, necessary for missionary work in the post-sexual-revolution age, and that once they’re accomplished, the subsequent renewal will justify the means. The second is that because conservative Catholics are so invested in papal authority, a revolution from above can carry all before it: the conservatives’ very theology makes it impossible for them to effectively resist a liberalizing pope, and anyway they have no other place to go.

But the first assumption now has a certain amount of evidence against it, given how many of the Protestant churches that have already liberalized on sexual issues—again, often dividing in the process—are presently aging toward a comfortable extinction. (As is, of course, the Catholic Church in Germany, ground zero for Walter Kasper’s vision of reform.)

Contemporary progressive Catholicism has been stamped by the experience of the Second Vatican Council, when what was then a vital American Catholicism could be invoked as evidence that the Church should make its peace with liberalism as it was understood in 1960. But liberalism in 2015 means something rather different, and attempts to accommodate Christianity to its tenets have rarely produced the expected flourishing and growth. Instead, liberal Christianity’s recent victories have very often been associated with the decline or dissolution of its institutional expressions.

Which leaves the second assumption for liberals to fall back on—a kind of progressive ultramontanism, which assumes that papal power can remake the Church without dividing it, and that when Rome speaks, even disappointed conservatives will ultimately concede that the case is closed.

It is a brave theory. We will soon find out whether Papa Francesco intends to put it to the test.