Good question. So far the Western nations have been slow to respond to the ethno-religious cleansing of Christians, and not just in Iraq, as World Jewish Congress president Ronald Lauder writes in his essay in today’s New York Times. Other than anodyne calls for tolerance and peace, the Western world of Christendom has had little to say or do about what John Allen called The Global War on Christians in his book of the same name. That bodes ill not just for Christians but for all oppressed minorities, Lauder writes, and calls on Jews to come to the defense of Christians:

The Middle East and parts of central Africa are losing entire Christian communities that have lived in peace for centuries. The terrorist group Boko Haram has kidnapped and killed hundreds of Christians this year — ravaging the predominantly Christian town of Gwoza, in Borno State in northeastern Nigeria, two weeks ago. Half a million Christian Arabs have been driven out of Syriaduring the three-plus years of civil war there. Christians have been persecuted and killed in countries from Lebanon to Sudan.

Historians may look back at this period and wonder if people had lost their bearings. Few reporters have traveled to Iraq to bear witness to the Nazi-like wave of terror that is rolling across that country. The United Nations has been mostly mum. World leaders seem to be consumed with other matters in this strange summer of 2014. There are no flotillas traveling to Syria or Iraq. And the beautiful celebrities and aging rock stars — why doesn’t the slaughter of Christians seem to activate their social antennas? …

The general indifference to ISIS, with its mass executions of Christians and its deadly preoccupation with Israel, isn’t just wrong; it’s obscene.

In a speech before thousands of Christians in Budapest in June, I made a solemn promise that just as I will not be silent in the face of the growing threat of anti-Semitism in Europe and in the Middle East, I will not be indifferent to Christian suffering. Historically, it has almost always been the other way around: Jews have all too often been the persecuted minority. But Israel has been among the first countries to aid Christians in South Sudan. Christians can openly practice their religion in Israel, unlike in much of the Middle East.

This bond between Jews and Christians makes complete sense. We share much more than most religions. We read the same Bible, and share a moral and ethical core. Now, sadly, we share a kind of suffering: Christians are dying because of their beliefs, because they are defenseless and because the world is indifferent to their suffering.

Lauder gives Obama credit for coming to the aid of the Yazidis, but notes that a few airstrikes are not a coherent strategy to defend oppressed minorities. At least it’s something, though, which is more than can be said for most of the rest of the Western nations on this issue.

Thankfully, Lauder isn’t alone in calling for a strategic, unified response. Pope Francis called for the world to act to stop the “unjust aggression” in Iraq against defenseless minority communities, especially but not limited to the Christian communities that go all the way back to St. Thomas the Apostle. That seemingly flies in the face of Christian pacifism, but that has its limits, as I write in my column for The Week:

Has the Vatican abandoned pacifism? Not exactly. While Vox and others hyperbolically suggested that Francis had issued a call for a new crusade, the pontiff hardly asked for a Western campaign of conquest. Francis’ remarks fall within what could be called a tradition of conditional pacifism, one that recognizes the limits of dialogue and negotiation in the prosecution of violent evils such as genocide. Francis seeks the restoration of peace, which on occasions means the use of force for that purpose — and that purpose only.

It may come as a surprise to many that the Catholic Church still adheres to the “just war” doctrine, which applies to the gap left when negotiation and dialogue either fail or have no rational application. The Catechism, which outlines the application of Catholic faith in the world, expressly notes the circumstances in which this occurs, as well as the strictures for operating within Christian morality when it occurs. For armed resistance to have moral legitimacy, it has to meet five conditions set out in paragraph 2243:

1) there is certain, grave, and prolonged violation of fundamental rights; 2) all other means of redress have been exhausted; 3) such resistance will not provoke worse disorders; 4) there is well–founded hope of success; and 5) it is impossible reasonably to foresee any better solution.

Few would doubt that the situation in northern Iraq meets the first condition, and the proclaimed commitment by ISIS to genocidal policies such as murder, rape, and displacement offer no rational options for the second. One shudders to imagine a worse outcome than the present for the Yazidis, the Christians, and the heterodox Muslims facing annihilation or slavery, so the third condition is almost a moot point.

That leaves us with the fourth and fifth conditions for armed resistance (and by extension, armed intervention). One can argue that it’s so impossible to see a reasonable alternative to armed intervention because there isn’t much hope of success even in that direction, but those two points are the most debatable of these conditions. To shrug off any responsibility on the basis of difficulty, however, is to condemn thousands of people in Iraq to slavery — or worse — under the brutal and evil reign of ISIS and their self-proclaimed caliph, Abu Bakr al-Baghdadi.

My column prompted a rejoinder from my colleague at The Week, Damon Linker, who reminded us of his own take on this last March:

Just war theory took shape in the writings of Augustine, Thomas Aquinas, Francisco de Vitoria, Francisco Suárez, and Hugo Grotius — some of the leading thinkers of Christian civilization — and it was championed in the 20th century by two of Christianity’s most celebrated intellectuals and apologists, Reinhold Niebuhr and C.S. Lewis.

But that doesn’t mean that these thinkers were justified in treating Christianity as compatible with war-making — any more than the choice of Christian popes, kings, and aristocrats to fight the Crusades automatically makes those wars of imperialistic conquest consistent with the teachings of Jesus Christ. …

Reason is a powerful tool, one we should respect and rely on as we think through any number of issues. But it’s also almost infinitely plastic. Given the right premises, it can justify nearly anything. Which is why you should never trust it entirely with your life — or the lives of others.

By all means, let’s argue about war and peace, justice and God. And if, after all the arguments have been made, we’re thoroughly convinced of the need to drop bombs and deploy troops, then let’s go to war, with as much restraint and humility as we can muster.

But please, let’s not make fools of ourselves by imagining that in doing so we have Jesus Christ on our side, nodding and smiling at the slaughter.

I don’t imagine any such thing, actually, and I’m equally certain Pope Francis doesn’t either. I don’t suppose Jesus is smiling at the deaths caused by the airstrikes even while they save the lives of innocent and defenseless people of several faiths. I also suspect he’s not smiling at the barbarity of ISIS as it sweeps across the desert of Iraq and Syria. And while I agree that reason is infinitely plastic or very nearly so, there is a rather large moral inequivalence between genocide and slavery, and the use of force to prevent either or both.

Furthermore, I’m not arguing that Jesus would applaud a military intervention anyway. Pacifism is, and should be, the first impulse of the Christian, and the second and third impulse as well. We are called to prayer and to make peace — when peace is possible. What Pope Francis and the Catholic Church in its Catechism argue is that war should be a last resort, and that it should be fought with “as much humility and restraint as possible.” My column points out what Francis meant, and why a fight to stop ISIS fits within the paradigm presented in Catholic teaching.

That’s why the Just War doctrine exists at all — to distinguish between wars of necessity and wars of choice. War is a result of a fallen world, which Christ offered salvation to those who accept it of their own free will. But the fallen world remains, and with it difficult moral choices as to the proper use of power for the good of humanity. Most wars are fought over petty concerns over territory, power, or even ideology, but some of those in the latter category involve such intrinsic evil with which it is impossible to negotiate or allow to continue unabated. Leaving victims to die at the hands of evil sadists and standing on the sidelines while entire populations get erased or sent into slavery is a choice, yes, but it’s not one compatible with Christian teaching either.