Not all ISIS fighters who surrender survive the attempt. The forces to whom they submit are also those whom they have most wounded. And, flush with the fervor of war, Iraqi soldiers have already executed captives. But, if Iraq is to have any hope of rescuing peace from the sectarian divisions which have riven the country, then its government must ensure that captured suspects face judgements more rigorous than those dispensed on the battlefield. Similarly, if the United States intends to give real meaning to its interminable desert intervention, then it should insist on judgement by law, not passion.

Sorting the guilty from the innocent may appear a Herculean task, but it is not the first time that America has faced the problem. We were, after all, a part of the coalition that wrested Europe from Nazism. In confronting ISIS, we would be well served to draw lessons from the past.

Much as ISIS does today, the Nazis fought to forge a new world through conflict. Both ideologies have induced their adherents to view every locale as a field of battle, and to treat every individual as a combatant. Whether in Europe or the Middle East, these sorts of revolutionaries define final victory as a redemptive, transcendent process that will wipe away a corrupted past. To achieve it, they deploy common soldiers as the agents of uncommon hatred.

Long after Germany’s terrorism was ended, the survivor Elie Wiesel summarized its significance. The Holocaust was so jarring, he wrote, that everything we use to orient our understanding of the world – the “traditional ideas and acquired values, philosophical systems and social theories – all must be revised in the shadow of Birkenau.” Besides the human toll which it exacted, the ethicist John K. Roth writes that the Holocaust “did enormous harm to ethics by showing how ethical teachings could be overridden, rendered dysfunctional, or even subverted to serve the interests of genocide.”

The reign of the Islamic State has reiterated those lessons. They burned people alive and, in reveling in other gory displays, took their satisfaction from cruelty. As with the perpetrators of the Holocaust, it is too easy to imagine that the masked figures who stood before the cameras as the agents of ISIS’ destructive ethos are not human at all. It is easier still to dismiss anyone who served them as unworthy of consideration. But we would be wrong to do so. Excluding them from humanity only deepens the harm that they have already done.

The leaders of the allied forces arrayed against Nazism realized as much. Disheartening and alien though Nazism’s brutality had been, those who opposed it understood the value of addressing it directly in terms already familiar to the civilized world. Their duty was to rescue the universalizing principles of human rights from the muck in which Nazism had tried to bury them.

To that end, the victors resolved to meet cruelty with justice, and together declared their intent in a joint statement on atrocities. Any German, they warned, who had “taken part” in “atrocities, massacres and executions” would be tried by law. President Roosevelt’s hope, expressed in the depth of war, had been to avoid “mass reprisals.” He recognized that revenge would sow future conflict, so he made clear that our interest extended only so far as securing “just and sure punishment” according to the law.

There is no claim here that the Allied powers were immaculate paladins of justice, or that their system of trials is unimpeachable. What is more important than their faults, however, is that which they strove for. By judging the worst brutalities in the same manner that the law approaches common criminality, we insisted that such actions lay within our power to rebuke.

That we have the power to do so creates an equivalent duty. Because extremists defy the principle of equality, they attack any tradition that gives it meaning. They will forever seek to obliviate the rule of law. The great danger in confronting them is, therefore, the risk of validating their derision by conceding exceptions and departing from principle in order to meet their outrages. If ISIS’ defeat in Iraq takes the form of one group yet again revenging itself against another, then the victory will be pointless. It is only by insisting upon the rights of any captive that we strengthen those ideal and value laden pillars which Elie Wiesel had lamented as broken.

As verse 47:4 of the Quran instructs, when the enemy has been subjugated “thereafter (is the time) either for generosity or ransom.” Surrendered fighters need not be granted parole free of consequence, but whatever punishment they receive must come only after public trials which demonstrate that institutional justice is available to all without prejudice or favor. It is only when that is true that people will no longer turn first towards strength of arms as a response to perceived injustice.

In this regard, the United States has a duty to lead with an eye towards history. As was unfortunately proven yet again in New York yesterday, the issue of fanaticism transcends national borders, and how we respond in this moment will define our country for years to come. We now hold not one, but two surrendered fighters in our custody. The first is an American who is being held incommunicado somewhere in Iraq, and the second is a legal resident of the United States. Though Donald Trump mocked our system of justice as “a joke,” and “a laughingstock” and promised something “much tougher,” abandoning due process will doom this country more surely than any number of terrorist attacks.

Contrary to President Trump’s intimations that adherence to principle harms us, bringing these fighters before regular courts to face trials as civilians would be an affirmation of our national security. As Justice Robert H. Jackson remarked at the convocation of the Nuremberg Trials, “even in victory and when stung by injury,” that we may “stay the hand of vengeance and voluntarily submit [our] captive enemies to the judgement of the law is one of the most significant tributes that Power has paid to Reason.” Affording our prisoners the rights guaranteed by the Constitution will be an example to the world and all Americans of their strength.

By again committing ourselves to the ideal of justice even when its administration seems least convenient, we will honor the lessons of the past and strengthen the hard-won principles that we have so long fought to defend. Guaranteeing due process to captured ISIS fighters will be a victory over anyone who insists that the only sure rule in this world is force, and an encouraging sign for aggrieved individuals who might otherwise have been tempted by ISIS’ philosophy of struggle and recrimination.