As we head into the fourth month of Russia’s war against Ukraine, we read commentary in recent days suggesting that Ukraine is another “Cuban Missile Crisis” and represents “the most serious European military conflict since World War II.” Accordingly, the perception is that Ukraine resembles Korea. That is, it is immensely important, given the utterly unjust nature of the war as well as the consistent nuclear saber-rattling emanating from Moscow, but it is outside of the United States’ immediate interests. More significantly, it invites World War III.

In advance of capitulating to apocalyptic scenarios, we do well to recall Vladimir Putin’s framing of the war and its twofold justification. It accords with Russia’s longstanding commitment to return Ukraine to the fold—as part of mother Russia—and it represents a civilizational battle against the West, which since 1989 has been responsible for the demise of the Soviet empire. This demise, as Putin has vehemently insisted, is “the greatest geopolitical tragedy of the twentieth century.” As former US Ambassador to the United Nations John Bolton has observed, Putin clearly aims to “re-establish Russian hegemony within the space of the former Soviet Union,” and “Ukraine is the biggest prize.” Hence, his longstanding disdain for Ukrainian nationhood and opposition to its joining the NATO alliance.

Among the latest of Moscow’s veiled nuclear threats is that of Russian Foreign Minister Sergey Lavrov, who in late April warned of a “serious” and “considerable” risk of nuclear war over Ukraine. This followed Putin’s April 20 announcement at a test-launch of a nuclear-capable intercontinental ballistic missile aimed at the US and NATO members to “think twice” about abetting Ukraine. His statement came four days after his warning of “unpredictable consequences” that followed President Joe Biden’s commitment of $800 million dollars in military hardware to the war effort. That warning, it will be remembered, came on the heels of the warning by Dmitry Medvedev, deputy chairman of the Russian Security Council, that Russia will be forced to strengthen its nuclear forces in the Baltic region should Finland and Sweden proceed with their application to join NATO.

In our day it is difficult for some, perhaps many, to recall that the West’s Cold War policy of nuclear deterrence—anchored in traditional just war moral principles of just cause, right intention, proportionality, and discrimination—helped avert war rather than increase the prospects of nuclear conflagration. Why? It was the matter of deterrence.

Nuclear weaponry has been with us now for the better part of a century. Just war scholar Darrell Cole has identified three logical scenarios in which the use of nuclear weapons could be both proportionate and discriminate, and therefore justifiable: (1) destroying an adversary’s nuclear, biological, or chemical arsenals; (2) destroying deeply buried targets that are impervious to conventional attacks; and (3) denying ultimate victory to an adversary.[1] Particularly relevant here are the just war criteria of intention, deterrence, discrimination, and proportionality, especially in light of the widespread fear that nuclear weapons are inherently unjust and thus incapable of being discriminating and proportionate to the threat. Cole observes a sliding scale in the use of such deterrent weapons. At one end are high-yield, low-precision weapons such as are typically depicted in science fiction; at the other end are low-yield, high-precision weapons employed in the direction of strategic military objects and where harm to non-combatants is decidedly limited. Any just use of nuclear weaponry must intend to target military objects and not non-combatants. “Discrimination,” properly understood, concerns not numbers (i.e., how many) but who and why. The aim must be to remove or immobilize military targets that are bent on wider destruction.

Here we encounter the principle of double effect, originally formulated by Thomas Aquinas, according to which an act may have two effects—one of which is intended. The key question is this: Is good or evil intended? Innocents might be harmed in the context of war, but they are not intended to be harmed. To the point, could a nuclear strike be intended to prevent evil? According to just war moral reasoning, the answer is yes, if the object is a military target and contextualized in the three above-mentioned scenarios. Moreover, a victory-denying strike (the third scenario) is neither preventive nor preemptive; it is a response to a first strike. Hence, its value as a deterrent.

A final word on deterrence—and specifically nuclear deterrence—is here appropriate. Deterrence has essentially two purposes: to prevent an initial nuclear strike and to hinder further enemy aggression. Deterrence, rightly understood, belongs to responsible statecraft and thus can serve just purposes. If we may not use nuclear weapons, then—logically—there is no deterrent at all, as Michael Novak in his Moral Clarity in a Nuclear Age has argued. In the words of Darrell Cole, we cannot separate our intention to deter from our intention to use. Cole’s position is consistent with classic just war doctrine, despite the many religious voices in our day and during the Cold War era to the contrary. (Even in recent days, Pope Francis has cast doubt on whether Ukraine has the right to defend herself in this entirely unjust war, having publicly offered the supremely unwise and uninformed comment that NATO’s “barking at Russia’s door” might have provoked the war.)

The present conflict is a war that Ukraine did not choose. Herein Russia has violated every behavioral norm and criteria put in place by post-World War II conventions. And we can be sure that no international court or tribunal will be calling Putin or Moscow into account in the days ahead. Such is the nature of totalitarianism.

Confronting the West (i.e., the US and NATO nations) is the moral obligation to deter nuclear catastrophe—an obligation that we essentially laid to rest three decades ago in the interest of appeasing totalitarian regimes. Russian military doctrine, though we are inclined to forget, allows for the nuclear threat, as the Cold War indicated. Moscow believes that we (the West) do not have the resolve (China believes this as well, not to mention North Korea or Iran). Yet one of the Cold War’s successes was the very fact that we did deter Moscow’s threat through tactical weaponry; the Soviet threat was deterred. The West did not succumb to nuclear blackmail.

Should we not rise to confrontation, we encourage Russia’s miscalculation and, in the end, greater atrocity. Given Moscow’s nuclear threats, we must confront moral reality, just as civilized nations are forced to do in the domestic context. Civilized societies do not tolerate the murder and annihilation of their members; only uncivilized do. If we do not embrace this moral reality and deter the criminal element in the community of nations, we invite losses that are incalculable and even greater evil in the days ahead.

[1] Darrell Cole, “Special Problems IV: Questions Posed by Nuclear and Other Weapons of Mass Destruction,” in James Turner Johnson and Eric D. Patterson, eds., Ashgate Companion to Military Ethics (Surrey, UK, and Burlington: Ashgate, 2015), 101-11.