In July 2017, the Iraqi military and Shia militias fought their way through Mosul's Old City against ISIS. The air was filled with concrete dust and the stench of rotting human flesh and feces, the heat a punishing 110 Fahrenheit. There were dead bodies here and there, ISIS and civilians, soldiers and hostages of a caliphate.

I stood in the ruins of al-Nuri Mosque, where that caliphate had been proclaimed three years before by the self-styled caliph, Abu Bakr al-Baghdadi. As medics tended to a wounded soldier who groaned repeatedly in agony that I hoped was sedated, I remember vividly how I wished in that moment that his cries could be heard thousands of miles away by those who in 2003 had set in motion the war that led to this.

Less than four years later, Pope Francis visited Mosul's Old City, much of which remains in rubble to this day. The human devastation is incalculable, with millions suffering trauma that will endure for generations. But Pope Francis was present and offered a message of hope. He also called himself a "penitent pilgrim," asking forgiveness for those who brought war to Iraq.

It is reasonable to infer from his statements that he believes it is the United States that is at fault. His predecessor Pope John Paul II, in a now well-known diplomatic intervention, sent Cardinal Pio Laghi to the White House in 2003 in hopes of preventing the U.S. invasion. That mission failed, of course, but Pio Laghi's warning proved prophetic: Iraq and much of the region descended into war and chaos, with consequences foreseen and unforeseen. America has yet to find a way out.

The U.S. took no particular interest in the plight of Christians after the 2003 invasion. After the first Gulf War in 1991, Saddam Hussein's regime regarded Christians with suspicion, for being sympathetic to the primarily Christian Americans. The U.S. was keen to maintain impartiality toward Iraqi Christians, but that came off as callous indifference, and in any case it did little good for Christians or other targeted minorities.

After 2003, Christians were targeted by both sides of the insurgency, caught in the middle of the Sunni--Shia civil war initiated by Abu Musab al-Zarqawi months after the overthrow of Saddam. From 2003 until 2014, the number of Christians in Iraq fell by nearly a million, to roughly 450,000 in 2014, most of them in northern Iraq. When Mosul fell, Christian homes were marked with the Arabic N for Nasara (Nazarene, or followers of Jesus). After Mosul, ISIS conquered much of the Nineveh Plain. The remaining Christians fled to Iraqi Kurdistan or simply left Iraq altogether.

Christians in neighboring Syria fared little better when war arrived there in 2010. Syrian Christians numbered over a million, about 10 percent of the population, before the civil war. Today there are half that many. Most of them fled, though many were also killed. When U.S.-backed rebels overthrew Muamar Qaddafi in Libya, it became, as in Syria, yet another haven for al-Qaeda and ISIS affiliates. When 21 Coptic Christian migrant workers, wearing orange jumpsuits, were marched onto a Mediterranean beach and beheaded in February 2015, few Americans took notice of the link to the U.S. prisons in Guantanamo Bay. This significance was clear to onlookers in the region, however: Christians in the Middle East are bound up with America and ought to be eradicated.

In Iraqi churches, ISIS wrote the term "Crusaders" on the wall, still another link between the local Christians and the West. The U.S. was simply indifferent to all this.

To be sure, the last two decades of military interventions in the Middle East have been disastrous, not only for the region's Christians and other minorities but for millions of others. But does the U.S. merit all the blame? Certainly it is blameworthy for waging an injudicious war, but many others exacerbated the situation in Iraq. Saddam's Baathist government carried out the very acts of terror and chemical weapons that Pope Francis condemned in last year's encyclical letter, Fratelli Tutti -- and that the United Nations, which Francis praises, was designed to prevent.

Then there were Syria and Iran, which readily supplied men and weapons for the years-long insurgency in Iraq. During that time, Iran initiated a substantial and illegal missile buildup in Lebanon that violates U.N. Resolutions 1701 and 1559. Iran has, through Hezbollah, made the Lebanon--Israel border perhaps the most unstable in the region -- quite possibly the locus of the next great war in the Middle East.

Lebanon, which Pope John Paull II once hailed as "a message" that religious pluralism is possible, is in the midst of a political and economic crisis that has pushed the state to the brink of collapse. Lebanon is the only country in the Arab world where Christians have a prominent role in the public culture. It is in many respects the most Western country, in large part owing to the Christian influence -- progressive by regional standards.

Perhaps one-third of Lebanon is Christian, mostly Maronite Catholics, but their numbers are dwindling, especially amid the economic crisis and the haunting threat of war. Patriarch Cardinal Boutros Rai recently spoke out to condemn both Lebanon's corrupt elite and, with some nuance, Iran's violation of Lebanon's neutrality. "There are no two states in one land," Cardinal Rai, a Maronite, told an outdoor audience in February, "and no two armies in one state." It was a clear reference to Iran and Hezbollah, to which many present chanted, "Iran, get out." One hopes those chants were heard in Rome, for war between Israel and Hezbollah would leave Lebanon in a rubble that resembles that of Mosul.

It may be a perfectly sound diplomatic strategy for the Vatican to put daylight between itself and the U.S. to curry favor with Middle Eastern -- or European or Asian -- governments. This was clearly the Vatican's approach during the Trump administration. But it must be said that the Trump administration did not begin any new wars and that Trump himself tried to conclude some. (Trump even managed to cite, however inadvertently, just-war theory in exercising proportionate response in his limited U.S. military strike against Iran.) No doubt many Vatican diplomats found diplomatic ties with the U.S. more distasteful than they did ties with Iran. But strong diplomatic relations alone with Iran will do little to help Christians to survive in the Middle East. It is now time to see what the Vatican plans to propose to help Christians in Iraq and elsewhere in the region. Simply blaming America for the ills of Iraq and the Middle East is not a plan.

Pope Francis and the Vatican have little regard for the conservative flavor of many Americans' Catholicism. To be fair, many such Americans were vocal supporters of the Iraq War, even though few had foreign-policy or military experience and were, in retrospect, quite simply out of their depth. (Some of these still-prominent Catholics led many Americans astray and quashed dissent among those who opposed the Iraq War; they should have apologized and gone quietly, but it turns out that there are second acts in American public life.) These Catholics in the public square may have forgotten Iraq and moved on to other disputes with the progressive pontiff. But he has not forgotten the Iraq War and, in this sense, he provides continuity with his predecessors. (Pope Benedict also expressed grave concerns about Iraq and its Christian community at his first meeting with President Bush in 2007.)

The question of the future of Christians of the Middle East has arisen among popes and statesmen for the past thousand years. The Council of Clermont launched the First Crusade in response to the Byzantine emperor's plea for military assistance against the expanding Turks. Four centuries later, the Council of Florence sought to reunify Greek and Latin, Orthodox and Catholic, Christendom to save Byzantium, now surrounded by the Turks. European powers variously sought to protect Christian and other minorities in the Middle East -- invariably against the Turks, who managed to murder or expel almost all their Christians. (Arguably the most noteworthy success story was Armenia, which reforged an ancient nation in the form of a modern state in the aftermath of genocide to ensure their survival.)

There is no reason to suppose that the papacy, whose influence is substantially diminished from earlier centuries, or America, exhausted by two decades of spilling blood and treasure in the Middle East, will offer a diplomatic solution that will preserve Christianity in the region. In the near term, there are five critical areas that will define the future of Christianity in the Middle East.

First, Lebanon. Unless there is a concerted diplomatic effort to save Lebanon from its political leadership and from Iran and Hezbollah, which exploit that corrupt leadership, Lebanon will collapse into anarchy.

Second, Egypt. The Copts are the largest Christian presence in the Middle East, but they are also the targets of open discrimination and frequently violence. Until Egypt's Christians are afforded equal citizenship, their numbers will likely decline.

Third, Armenia. Modern Armenia was established following the 1915 genocide by Ottoman Turkey. It is a living reminder that the formation of political community is often the only means by which distinct peoples can survive.

Fourth, the Christians of the Arab Gulf. Several million migrant and domestic laborers live in the Arab Gulf, although many have no recognized rights, including the right to worship.

Fifth, the Christians of the Shia Crescent. The Christians of Iran, Iraq, and Syria total more than a million, though their numbers are in decline. It may be that Pope Francis had these Christians in mind when he made his historic visit to Najaf to meet with Ayatollah Sistani.

It requires greater skill to anticipate an impending disaster and prevent it than to condemn a disaster after it has occurred. Only time will tell if Francis -- or the Biden administration -- has any vision for Iraq's minorities or for Christians and other minorities across the region. Some policy experts on the ground -- Joshua Levkowitz and Yousif Kalian, an American Syriac Christian, at the United States Institute of Peace -- recently proposed policies aimed at decentralization and local governance, which are long overdue in Iraq and might save what remains of the Christian presence there. Such a model might be replicated elsewhere in the Middle East, where over-centralization increases inefficiency and corruption and diminishes social trust. To solve these problems will require time that most diplomats -- though they will never say so -- likely intend to spend elsewhere.

During World War II, American-led bombing raids against Nazi-occupied Belgrade killed so many civilians that the Serbs said, "God save us from American help." That Serb saying is fitting for U.S. involvement in the Middle East, which was, despite what many believe, undertaken with the best intentions. But the aspirations behind that intervention were not tempered by prudence. For their part, the Christians of the Middle East have endured discrimination by their governments, persecution by their neighbors, indifference from Americans, slaughters on the shores of the Mediterranean, the desecration of the tombs in Mesopotamia -- and yet they are still there.

Some believe that a Catholic president and a progressive pope may work together to achieve some grand vision -- the liberal version of the Ronald Reagan--John Paul II alliance. It is difficult not to be skeptical of any such partnership bearing fruit, certainly to the extent of the partnership that brought down Soviet Communism. And what would be the goal? Neither takes a particularly tough line on human-rights abuses in China, the most significant challenge to the West and to the global order.

Perhaps the president and the pope will have a humbler agenda. After Francis's visit to Iraq, the Christians of the Middle East hope that they are on that agenda -- that Francis does not simply consider his work to have concluded with his remarks from the ruins.