When Pope Francis and President Donald Trump meet on Wednesday, the almost irresistible temptation likely will be to focus on the “Odd Couple” dynamic of the encounter. Symbolically, Francis is the third-world man of the people, Trump the incarnation of “America first” swagger.

However, what should not be lost is that this meeting is not just about two personalities colliding, however riveting they may be, but about two institutions: The United States and the Holy See.

As former U.S. Ambassador to the Holy See James Nicholson puts it in a forthcoming Crux interview, the Vatican is the world’s leading spiritual superpower and the U.S. its most important temporal power, so when these two players are in alignment, the plates of history can shift.

On his way back from his trip to Fatima last weekend, Pope Francis said that in the meeting he wants to seek “doors that aren’t closed” to possible cooperation, and presumably Trump too will want to come away with something positive to talk about – if, for no other reason, than as a welcome bit of good news amid what has been a fairly rough stretch for the administration.

Where might that “open door” be found?

There are a number of possibilities, but let me float one here that ought to be fairly easy for both sides to embrace, and which could have a decisive impact on the ground in one of the world’s most perennially troubled regions.

By now, everyone knows that Christians and other minorities in Iraq and Syria are the targets of a genocidal campaign by ISIS extremists. The Islamic State’s ability to carry out that aim may wax and wane with its military fortunes, but there’s no doubt about the ultimate objective of exterminating minority groups in the territory under its control.

Both Francis and Trump have called for solidarity and greater protection for those persecuted Christians, so in broad strokes there would appear to be the basis for some common cause.

What’s less well known, however, is a chronic problem with delivering humanitarian aid to those Christians.

The issue is this: Funding from both the U.S. and the U.N. dedicated to relief for ISIS victims is generally allocated either to governmental bodies or NGOs, and in both cases the aid it buys is usually distributed in large refugee camps, such as those erected in the Kurdish city of Erbil. The problem is that Christians often avoid those camps, out of fear of being further exposed to militants and ISIS sympathizers.

As a result, much of the humanitarian aid flowing into Iraq and Syria never reaches Christians directly, who prefer to receive help from Church facilities such as shelters and convents, where they know they’ll be safe. Were it not for organizations such as Aid to the Church in Need, Catholic Relief Services and the Knights of Columbus (Crux’s principal partner), those local Christian institutions would have run out of help to give a long time ago.

Those resources, however, are not infinite, and the need continues to grow.

In August, Archbishop Jean-Clément Jeanbart, the Greek Melkite Archbishop of Aleppo in Syria, appealed to international organizations to entrust a portion of their budgets for humanitarian relief to the churches of the region, to ensure that it actually reaches the Christians who need it.

“If the help went to the churches, it wouldn’t mean that they’re giving special rights to Christians, but that they’re actually helping everyone,” Jeanbart said.

To date, however, those appeals have fallen on deaf ears.

Candidate Trump vowed to make persecuted Christians in the Middle East a U.S. foreign policy priority, and he’s continued to make similar statements since taking office. Within the last month, both he and Vice President Mike Pence have expressed support, with Pence telling a May 11 summit on persecuted Christians, “We’re with you, we stand with you,” and saying that both he and Trump pray for them.

Translating that rhetoric into action, however, is a more complicated matter.

Trump pulled back from an initial attempt to fast-track Christians and other ISIS victims in terms of refugee resettlement in the face of strong political opposition, and so far he hasn’t launched a major military campaign to “soundly and quickly defeat ISIS,” which is what he promised during the campaign – presumably, at least in part, because doing so is terribly complicated both logistically and strategically.

However, one thing a U.S. president could do immediately is to announce that a portion of American overseas humanitarian and development spending earmarked for Iraq and Syria will be allocated to the churches of those two countries, to ensure that Christians get their fair share.

The federal budget adopted in early May by the U.S. Congress includes roughly $1.4 billion in humanitarian assistance for “vulnerable and persecuted religious minorities, including victims of genocide designated by the Secretary of State and other groups that have suffered crimes against humanity and ethnic cleansing.” If even some small share of that funding were to be set aside to be administered by churches in the Middle East, it could make a vast difference.

To be clear, this is not about preferential treatment, but ensuring that aid designed for an especially vulnerable population actually goes where it’s intended.

If Pope Francis were to make the case for doing so with Trump and his aides, and if Trump were to bite, it would provide swift relief for suffering people, not to mention a diplomatic win for the Vatican and a rare bit of positive news for Trump – one that should also play well with the religious voters who formed an important part of the president’s electoral base in November.

Let’s face it: There really are only two leaders in the world with either the resources or the boots on the ground in the Middle East to make any difference for Christians struggling to survive there, and they’re the U.S. president and the pope.

Since they’re meeting three days from now, it will be fascinating to see if they seize the opportunity.