You know it was a scintillating papal press conference this week when, in reply to a question about Donald Trump, the pontiff described the GOP candidate’s stance on immigration as “not Christian,” and arguably it wasn’t even the most important thing the pope said.

In the same news conference, Francis suggested he’s open to the idea of artificial birth control as a means of trying to combat the spread of the Zika virus in Latin America, while emphatically taking abortion off the table.

That answer was more than political theater. While a pope can’t dictate the outcome of an American election, he certainly can control what the Catholic Church approves.

To be clear, Francis did not say he was formally endorsing birth control to prevent infection. He also did not signal any shift in the Church’s negative stance on contraception as a means of preventing new life.

But he definitely left the impression that he’s open to viewing birth control in some limited cases as a legitimate anti-infection tool, a point confirmed by a Vatican spokesman on Friday who said it could be “the object of discernment in a serious case of conscience.”

While we wait for the debate that’s sure to follow, it’s worth noting that the pope’s answer provided a window into how the Vatican works that shouldn’t be overlooked.

Speaking about birth control in the context of the Zika pandemic, Francis cited his predecessor, Pope Paul VI. Here’s what he said, translated from Italian:

Paul VI — the great! — in a difficult situation, in Africa, permitted sisters to use birth control for cases of violence. It’s necessary not to confuse the evil of avoiding pregnancy, by itself, with abortion … avoiding pregnancy is not an absolute evil, and in certain cases, as in that I mentioned of Blessed Paul VI, it was clear.

The reference is to Congo in the late 1950s and early 60s, where Catholic nuns faced widespread sexual violence and the question was whether birth control could be used to avoid pregnancy after rape.

Francis said Paul VI “permitted” birth control in that context, which, to Anglo-Saxon ears, implies a formal juridical act. The line sparked a frenzy of fruitless Internet searches, as people went looking for a Vatican edict or decree that just doesn’t exist.

Here’s what happened: In December 1961, the influential Italian journal Studi Cattolici (“Catholic Studies”) published an issue in which three Catholic moral theologians agreed that in the Congo case, contraception could be justified.

The future Paul VI, at that stage, was still the Archbishop of Milan, and close to the currents that shaped Studi Cattolici. It was assumed the conclusions reflected his thinking. That appeared to be confirmed later when Paul VI made one of the authors, Pietro Palazzini, a cardinal.

Paul became pope in 1963, and never issued any edict writing that position into law. Thus, when pressed about it some years later, a Vatican spokesman could accurately say, “I am not aware of official documents from the Holy See in this regard.”

Still, the Vatican never repudiated the 1961 position, so the takeaway was that it remained a legitimate option. To Italians — and remember, Francis’ ancestry is Italian, and he’s very wired into the country’s ecclesiastical scene — that meant Paul VI approved.

All this is not terribly different from the way the Vatican has approached condom use in the context of a married couple where one partner is HIV-positive and the other isn’t, and the aim is to prevent the other partner from becoming infected.

In 2006, Pope Benedict XVI asked the Pontifical Council for Health Care under Mexican Cardinal Javier Lozano Barragán, who has since retired, to examine the question. After polling doctors and other health care professionals, as well as theologians, Barragán presented the pope with a tentatively positive response.

To date, that conclusion hasn’t been codified, but it also hasn’t been rejected. In 2010, Benedict said in an interview — note, an interview, not a formal dogmatic statement — that although the Church does not regard condoms as the solution to the AIDS crisis, there are cases in which they may be “a first step” toward responsible behavior.

In both cases, the moral analysis shifts because birth control is being used not to block the transmission of life, but to prevent the infliction of a harm — either unwanted pregnancy as the result of violence, or infection by a deadly disease.

John Grabowski, a moral theologian at the Catholic University of America, points out that the reasoning behind the 1960s-era position has been translated into Church practice.

In the United States, Grabowski noted, Catholic hospitals are allowed to administer fast-acting oral contraceptives to rape victims if tests show ovulation has not yet occurred and the effect is not to induce an abortion. Germany’s bishops confirmed a similar stance in 2013.

Often, the Vatican prefers to leave such delicate questions open, not issuing sweeping declarations that could be wrongly viewed as a sea change in Church teaching, but also not denying flexibility to pastors who have to help people make hard choices.

Quite possibly, that’s what Francis was doing on the papal plane with regard to the Zika virus. Given Latin America’s large Catholic population, it could have important consequences.

That’s not quite the formal decree some may want, or fear, but it also may be the only thing we’re likely to get.