It's not often that real life generates a laboratory experiment to help settle a historical debate, but Italian politics may create just such a chance to shed light on a key biographical question about Pope Francis.
Given that the issue is the legal status of same-sex relationships, the thinking of the pope is obviously of more than merely historical interest.
Before his election to the papacy, the line on Cardinal Jorge Mario Bergoglio of Buenos Aires, Argentina, was that he profiled as a fairly conventional conservative, in part because of his role in Argentina's bitter 2010 national debate over gay marriage.
That dust-up occasioned some of Bergoglio's most fiery political rhetoric, expressed in a July 2010 letter to Argentine monasteries asking them to pray for the initiative to fail.
"Let us not be naive: this is not simply a political struggle, but it is an attempt to destroy God's plan," he wrote then. "It is not just a bill but a move of the Father of Lies, who seeks to confuse and deceive the children of God."
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In the end, however, Argentina became the first nation in Latin America to adopt same-sex marriage.
How to square that seemingly hard-line 2010 stance by Bergoglio with perceptions of Pope Francis today as a political moderate, determined to dial down the culture wars, and a pontiff of outreach to gays who famously said, "Who am I to judge?"
There are two basic theories.
One is that the 2010 letter is the real Francis, and that the current fascination with his velvet glove ignores the iron fist underneath. Give him time, this theory holds, and he'll show his true colors. (That view tends to be popular among both cultural conservatives who want the pope to draw lines in the sand and gay rights activists who fear he'll do precisely that.)
The other theory holds that the 2010 letter was not the real Bergoglio, that quietly, he was willing to accept a compromise solution for civil unions as an alternative to gay marriage, and he adopted a rigid stance in public only because he was president of the bishops' conference and felt compelled to articulate the majority view.
Argentine Fr. Jorge Oesterheld, who served as the spokesperson for the bishops' conference in Argentina for the six years Bergoglio was its president from 2005 to 2011, made precisely that claim in an April interview with NCR.
"Some [bishops] were more inflexible than others," Oesterheld said. "The cardinal went along with what the majority wanted. He thought it was his job as president of the bishops' conference to support what the majority had decided, and he didn't impose his own views on the other bishops."
Italian politics shortly may give Francis another bite at the apple.
On Thursday, the charismatic new leader of the center-left Democratic Party, Florence Mayor Matteo Renzi, laid out key elements of his program in a letter to party leaders. Polls show the 38-year-old Renzi a favorite to become the country's next prime minister.
One element in that program is support for civil unions, along the lines of the 2005 "Civil Partnership Act" in the United Kingdom adopted under the Blair government.
Given the strongly Catholic ethos of Italy, observers believe full marriage rights for same-sex couples is improbable, but polls show public support for civil unions.
"These aren't civil rights but civil duties," Renzi said. "How can a country that doesn't take these issues seriously call itself civilized?"
Despite popular backing, political experts in Italy consider it a somewhat bold stance given that support for a similar measure back in 2006-2008 helped bring down the second government of center-left Prime Minister Romano Prodi.
Prodi backed a civil union measure known by the Italian acronym "Dico," which stirred ferocious opposition from the Italian church. It was led by the ultra-powerful president of the bishops' conference at the time, Cardinal Camillo Ruini, with the strong backing of the Vatican and Pope Benedict XVI.
The proposal died on the vine in 2008 when Prodi lost a no-confidence vote in the Italian senate and resigned.
Assuming Renzi follows through, the push for civil unions may be back under a future center-left government, and the drama would then become: Will the response under Francis be different?
Based on the tone already set by the new pope, many observers expect it will. Writing in today's La Stampa, journalist Fabio Martini claimed that in the Francis era the so-called "theo-cons," meaning politicians who invoke Christian values to defend conservative positions, "have become voiceless, and it will be difficult to recover their vigor."
Two caveats are in order.
First, Francis has said repeatedly that the church should not take directly political positions, and thus may be unlikely to express himself explicitly. Second, he's also a strong believer in collegiality, and would likely let the Italian bishops take the lead.
That said, the new regime in the Italian bishops' conference will doubtless be anxious to take its cues from the pope. Francis is putting his own stamp on the group's leadership, having recently named Bishop Nunzio Galantino of the Cassano all'Jonio diocese as its secretary.
By the time a hypothetical Renzi government would take over, the reins should be firmly in the hands of Bergoglioistas.
On Thursday, Maurizio Gasparri, the center-right vice-president of the Italian Senate, said the critical variable in the looming debate will be how Catholics in both major coalitions react.
For the wider world, however, the more intriguing question is likely to be: How will Francis react?
(Follow John Allen on Twitter: @JohnLAllenJr)