As summer turns to autumn, the most compelling storyline in Rome is a highly anticipated summit of Catholic bishops from around the world, which shapes up as a key test of how much the status quo in the Church has been upended by a charismatic pope from a foreign land who’s taken the world by storm.

Called a “Synod of Bishops”, the meeting seems destined to grapple with the contentious issue of the Church’s ban on divorced and remarried Catholics receiving Communion. Although the Vatican’s German doctrinal czar warns no change is possible, his admonition does little to stifle the debate.

A cardinal considered a lion of liberal European Catholicism uses a platform in Rome to argue for a more compassionate approach, based on the Orthodox model of penance after a first marriage breaks down. More conservative prelates insist that any liberalization would run afoul of a teaching that comes from Jesus himself: “What God has joined, let no one separate.”

As anyone who’s been paying attention knows, those lines fit like a glove in the run-up to this year’s Synod of Bishops on the family in Rome Oct. 5-19, convened by Pope Francis.

In fact, however, they date to October 1999 and that year’s Synod of Bishops on Europe, called by Pope John Paul II. At the time, luminaries of the left such as Cardinals Godfried Danneels of Brussels and Carlo Maria Martini of Milan were pushing to re-open a question that John Paul’s Vatican had declared closed five years before.

In 1993, three German bishops had put out a pastoral letter addressed to Catholics who divorce and remarry without obtaining an annulment, a declaration from a church court that a marriage never existed because it didn’t meet one of the tests for validity, such as informed consent. The bishops said if such Catholics decide in conscience their first marriage was invalid, with the counsel of a priest, they can receive communion.

A 1994 Vatican document from then-Cardinal Joseph Ratzinger (later Pope Benedict XVI), rejected that initiative by saying the communion ban is a matter of divine revelation and can’t be tweaked by individual bishops on their own.

At the 1999 synod, bishops seeking change tried to revisit that verdict. Famously, Danneels urged Catholicism to steal a page from the Orthodox, for whom sacraments are seen as “medicine for the soul” rather than a privilege earned by following the rules. Yet in the end, Ratzinger and other defenders of tradition held the line.

This brief remembrance of things past helps bring into focus what’s old hat about the divorce debate at the 2014 synod, as opposed to what’s truly novel.

1. Old hat: Bishops disagree with each other.

It’s not new that Catholic prelates have been trading blows in public, though it’s certainly been happening with vigor of late.

In October 2013, Archbishop Gerhard Müller, the Vatican’s doctrinal czar, published a lengthy essay in the Vatican newspaper arguing that Church teaching on the permanency of marriage is not open to question, basically repeating Ratzinger’s position from 19 years before. Francis later made Müller a cardinal.

In reply, Cardinal Oscar Rodríguez Maradiaga, the coordinator of the pope’s council of cardinal advisors, shot back that Müller “is a German, and above all he’s a German theology professor, so in his mentality there’s only truth and falsehood.”

“But I say, my brother, the world isn’t like this, and you should be a little flexible when you hear other voices,” Rodriguez said. “That means not just listening and then saying no.”

In February 2014, Francis summoned cardinals to Rome to set the table for the synod. To prime the pump, he turned to German Cardinal Walter Kasper. In 1993, Kasper had been one of those three German bishops who tried to open the door, and he had also been harshly critical of the Vatican’s negative 1994 response.

Kasper argued for relaxing the communion ban during his February speech, drawing a strong rebuke from Cardinal Carlo Caffarra of Bologna, Italy, who insisted that even the pope “has no power” to change a teaching rooted in Christ’s explicit teaching.

On and on it’s gone, with a slew of bishops taking positions either for or against rethinking the current discipline. Earlier this month, for instance, Bishop Johan Bonny of Antwerp, Belgium, put out a 22-page reflection on the synod which, among other things, calls for the Church “to explore how it can grant access to the Eucharist under certain circumstances to people who are divorced and remarried.”

2. Old hat: Catholics really care about this issue.

It’s also not new that the issue of communion for divorced and remarried Catholics is of tremendous grassroots interest.

In the U.S. alone, out of a total of nearly 30 million married Catholics, some 4.5 million are divorced and remarried without an annulment, according to Mark Gray at Georgetown University’s Center for Applied Research in the Apostolate. The global total is thought to include several million additional people.

Moreover, the number of Catholics marrying in the Church and the number of annulments both are in steady decline, which means that a growing host of Catholics are in “irregular” marriages and thus technically barred from receiving Communion.

Granted, some of these Catholics are non-practicing and don’t feel the sting of the ban. Granted, too, others have been quietly encouraged by their local pastor to receive Communion despite the rules. Nonetheless, the number of Catholics at least potentially affected vastly exceeds most other matters the synod seems likely to discuss.

3. Old hat: The arguments are familiar.

The arguments this time are basically the same as in the past, in part because it’s some of the same people making them.

For the left, it’s an issue of mercy, coupled with the ecumenical benefit of bringing Catholicism closer to Orthodox practice.

For the right, it’s about fidelity to tradition, with the political benefit of not showing weakness at a time when they believe traditional marriage is under secular assault.

1. What’s new? Guess who.

So what is different about 2014? In a word, it’s Francis, because for the first time, the pope’s heart seems to be with the reformers.

Francis got the ball rolling by taking a question about the divorced and remarried during an airborne press conference on his way back from Brazil to Rome in July 2013.

“I believe that this is a time of mercy,” he said. “The Church is a mother, she must go out and heal the wounded, with mercy.” He also cited the Orthodox practice of permitting a second marriage after a period of penance.

That didn’t quite mean the pope wanted change, but it left the impression he’s open to it.

Since then he’s dropped other hints, including the decision in February to tap Kasper to set the table.

Another came in April, when the Vatican played down, but never denied, that Francis called an Argentine woman named Jacquelina Lisbona whose husband divorced and remarried without an annulment, and whose local pastor refused to give her communion. Lisbona wrote the pontiff, who reportedly advised her to find a more understanding priest.

So fevered have expectations become that in October 2013 a Vatican spokesman had to plead with church leaders not to get ahead of the pope, asking them to wait for a policy change to be announced in Rome before implementing it on the ground.

2. What’s new? Nobody knows what’s going to happen.

Given all that, the primary difference in the 2014 Synod of Bishops is that for once, the outcome of the discussion seems genuinely uncertain.

On a related note, the other difference is the media interest the synod is generating.

That’s because the tug-of-war over divorced and remarried Catholics feeds into the single biggest question many people have about Pope Francis, which is the precise nature of the change he seems to want.

Is it all about tone and style, coupled with a more ardent concern for the poor? Or at some stage, will Francis also begin to revise Catholic teaching and discipline?

On most hot-button issues, Francis already has taken such moves off the table. His willingness to at least entertain it with regard to the divorced and remarried thus makes it a test of how deep his reforms will cut.

We won’t get an answer immediately, because this synod is actually designed to prepare for a larger one on the same subject next year. It’s tough to assess the odds of a breakthrough at the end of the road, in part because Francis has said he wants to act in concert with the world’s bishops, and some of those bishops seem certain to resist.

In a series of Boston Globe interviews in February, three leading North American cardinals – Sean P. O’Malley of Boston, Timothy Dolan of New York, and Thomas Collins of Toronto – came out against any change. Dolan reiterated his stance in a recent Crux interview, saying that relaxing the communion ban would “run up against the teaching of the church.”

Some African bishops have also voiced reservations about relaxing the communion ban, believing it would hurt efforts to break the grip of polygamy in their societies. If the church is perceived to be loosening its rules on marriage for the divorced, they worry, what would stop polygamists from also wanting special consideration?

At the level of political handicapping, observers expect most North Americans at the synod to oppose any change to the present rules, joined by many Africans. Europeans, Latin Americans, and Asians are expected to be more divided, but in any event, most forecasters don’t anticipate a strong consensus one way or the other.

In addition, Francis may be persuaded that there are options for helping the divorced and remarried short of overturning the communion ban, such as streamlining the annulment process and investing resources in church courts in regions of the world that don’t presently have them.

The bishops could also basically punt, deciding that these are individual pastoral judgments rather than anything that can be settled at the policy level, much like when a divided Congress decides to leave some hot-button matter to the states.

While those factors make it difficult to anticipate what Francis might do, they also enhance the drama of the synod. No matter which way things break, for two weeks in October, all eyes will be on Rome.