The Russian-Ukrainian War and Just War Theory

By Michael James Robblee

Estimated Read Time: 11 Minutes

As the Russian invasion of Ukraine continues, the world is all but unified in its denunciation of the war. While seemingly an intuitive conclusion, the reality is that our intuition is shaped by our worldview. We used to know so well that it became second nature; now, we cannot quite remember why we think the way we do. On these occasions, Americans often arrive at the right conclusion but asked to explain why, they cannot. They know the Russian President, Vladimir Putin, is devious but it is a vague impression. They know that this war is unjust but do they know just how unjust it is? It is imperative that Air and Space Force officers be able to think through these questions and provide clear, objective answers.

Modern Just War Theory is rooted in Christian thinking and is part of the fabric of Western Culture. It is important to understand the interconnectedness because Mr. Putin regularly casts himself as the defender of the Christian faith pitted against the West. Applying Just War Theory to current events in Ukraine can replace intuition and gut-feel with objectivity and certainty. This will help clarify thinking on the topic. Aurelius Augustine of Hippo, the great African Bishop (354-430 AD), supplies the criteria of Just War Theory and associated definitions. Augustine commands unimpeachable respect in both ecclesiastical and secular spheres. Among his titles are “Doctor of the Church” and “Doctor of the West.”

Built on Augustine’s thinking, modern conceptions of Just War theory are divided into two main headings: Jus ad bellum, justice in going to war, and Jus in bello, justice in conducting war. Under the first heading will be the following seven criteria: Just Cause, Comparative Justice, Right Intention, Competent Authority, Last Resort, Public Declaration, and Peace as the Ultimate Objective. Under the second heading will be Proportionality and Discrimination. Not all of the criteria are equally weighted, but all must be satisfied to enter and conduct war justly. The conclusion will not be surprising, but understanding will be deepened. In the following analysis, Russia’s actions will be evaluated against each Just War Theory component. While the analysis may seem cursory that is the purpose of the Just War Theory framework.

Justice in Going to War

Just Cause

According to Augustine, “as a rule just wars are defined as those which avenge injuries, if some nation or state against whom one is waging war has neglected to punish a wrong committed by its citizens, or to return something that was wrongfully taken.” Put simply, just war returns things to the way they were before and to apply punishment for wrong doing when appropriate. Just Cause is the sine qua non criteria, if this criterion is not satisfied, the war is not just. A key assumption is that this transaction occurs between the offending party and the aggravated party.

While Mr. Putin levied accusations at Ukraine in the past and claimed the existence of grievances that must be redressed, he has yet to produce the evidence. Credible evidence could lay the foundation for justifying war. Characteristically, Mr. Putin is obfuscating—tangling a random mix of unsubstantiated claims and unrelated ideas. He says, the West promised “not to expand NATO eastwards even by an inch. To reiterate: they have deceived us, or, to put it simply, they have played us…. Of course, this situation begs a question: what next, what are we to expect?” He explains that the USSR tried to avoid escalation in 1940. “As a result, the country was not prepared to counter the invasion by Nazi Germany.” He explains that NATO and the West “have publicly designated Russia as their enemy” and that “the leading NATO countries are supporting the far-right nationalists and neo-Nazis in Ukraine.” To summarizes: Ukraine must be demilitarized and denazified because the West and NATO “played” Russia. Mr. Putin conjured an impression; he did not provide a reason. There is no Just Cause.

Comparative Justice

Frequently, both parties in conflict possess a measure of justice. However, those with what Augustine calls the “juster cause” alone satisfy this criteria. Mr. Putin failed to present a Just Cause before invading Ukraine. Ukraine can appeal to homeland defense. In Augustine’s view, defending the homeland is clearly just because the fighters are defending “their life and liberty.” While Mr. Putin claimed that Russia must invade because it faces an existential threat, he did not provide any evidence. In contrast, all the world can see, Ukraine is facing an existential threat. Russia does not possess Comparative Justice.

Right Intention

Augustine cared deeply about the intentions of the heart. Intentions cannot be judged unless they are truly stated or become evident in space and time. We do well to remember that we can judge external things encountered in nature; but, judging hearts is the province of “nature’s God.” In the present, true intentions are always murky. Ancient wisdom teaches, you will know a tree by its fruit—actions reveal an individual’s intention. Russia’s recent history yields fruit for examination. In 2014, Russia invaded and annexed Crimea, a region considered then as now a part of Ukraine. With respect to territorial expansion, Augustine asks, “can good men consistently desire to extend their dominion? No.” Russia’s pattern of establishing in neighboring lands “arbitrary government, and enlarging its boundaries” is meant “at once” to be “an example and fit instrument for introducing the same absolute rule” in Ukraine. Mr. Putin’s intentions are not right.

Competent Authority

Augustine reserves the power to declare war to sovereign governments and holds that citizens, particularly members of the military, are obligated to answer calls to arms. Russia is a “free and independent” state with “full power to levy war” and “conclude peace.” Generally, no one is questioning Mr. Putin’s right to declare war in concert with the constitutional operation of the Russian government.

Last Resort and Public Declaration

Nations must seek redress by every avenue short of war before mounting an invasion. As described by Cicero, Ancient Rome would declare the insults and injuries that demanded satisfaction and enumerate the terms short of war that would remedy the situation. More recently, the United States Declaration of Independence reveals a similar approach as it catalogues “a long train of abuses and usurpation.” Indeed, it declared independence not war and was only a step in the process leading to war as it invited acceptance of the decision to separate and offered friendship in peace: “we must, therefore, acquiesce in the necessity, which denounces our Separation, and hold them, as we hold the rest of mankind, Enemies in War, in Peace Friends.” Next, a deadline for redress is established after which both sides understand all avenues short of war to be exhausted. Augustine lived at a time when the Roman Empire was on the defensive and not actively declaring war. Therefore, he did not need to take up the discussion about how to declare war justly. Cicero provides an analysis of Roman declarations of war and Augustine accepts his construction. Moreover, the Old Testament, which functioned for Augustine as the authoritative source of his worldview, handles the criteria in a similar fashion.

Mr. Putin did not follow this pattern. To the contrary, he claimed Russia had no intention of invading right up to the days and hours before it did. Meanwhile, his actions were at odds with his public statements as he amassed over 150,000 troops and weapon systems on the borders of Ukraine. Throughout the period used to build up his forces, Mr. Putin claimed that their presence along the Ukrainian border was to support various Russian and Russian-Belarusian joint military exercises. While the watching world detected the dissonance between his words and actions, Mr. Putin, nevertheless, failed to meet the demands of last resort and public declaration. 

Peace as the Ultimate Objective

Augustine declares, “war is waged in order that peace may be obtained.” For his part, Mr. Putin described his war aims in this way, “the purpose of this operation is to protect people who, for eight years now, have been facing humiliation and genocide perpetrated by the Kyiv regime.” Mr. Putin was referring to the ethnically-Russian people of Donetsk and Luhansk in the Donbas region of Ukraine. However, his reasoning conflates two kinds of ethnic Russians, ethnic Russians living peacefully in the Donbas region and Russian separatists in the Donbas region. However they got there, every nation of the world is home to people who are ethnic minorities. Nevertheless, their ethnic ties rarely imply a desire for their country of origin to conquer and rule the country they call home. The violence Mr. Putin refers to was sparked eight years ago by Russia’s invasion of the region and subsequent occupation by Russian-backed separatists. These are not people pleading with their king to treat them as free born Ukrainians. These are not people who “suffer, while evils are sufferable,” rather “than to right themselves by abolishing the forms to which they are accustomed.” These are Russian plants. If his invasion is successful, Mr. Putin is expected to install a pro-Russian government over all of Ukraine not just the Donbas region. With this government, Mr. Putin will seek, in his own words, to “demilitarize and denazify Ukraine, as well as bring to trial those who perpetrated numerous bloody crimes against civilians, including against citizens of the Russian Federation.” Mr. Putin is not seeking peace for Ukrainians but subjugation.

Justice in the Conduct of War


Proportionality is closely connected to peace as the ultimate objective. Augustine says, “he whose aim is to kill is not careful how he wounds, but he whose aim it is to cure is cautious with his lancet; for one seeks to destroy what is sound, the other what is decaying.” The purpose of war is not to inflict maximum injury on the enemy but to “lead them back to the advantages of peace.” For this reason, legitimate military objectives must be accomplished with the minimum violence necessary.

In many ways modern warfare can be characterized by terms like “precision,” “guided,” and “surgical.” The Russian military cannot be described this way. Mr. Putin’s strategy is siege warfare. If the enemy does not immediately capitulate, indiscriminate bombing ensues. Daily reports add to the list of cities Mr. Putin is attempting to raze. His sweeping actions do not align with his limited aims. If there are any oppressed to defend, if there are any atrocities to recompense, there is no military necessity to lay waste to all the population centers of Ukraine. Mr. Putin’s invasion is far out of just proportion even if we were to accept the justice of his claims.


The final criteria we will consider begins with the Augustinian understanding of agency. The executioner can administer the death penalty without being guilty of murder because he is an agent of the law. Nevertheless, Augustine warns that for the sake of one’s own conscience, necessity must perform the action rather than your will. Augustine discriminates between the public and private citizen; with respect to war, the relevant categories that emerge are combatants and non-combatants. Augustine begins with restricting military action to combatants. But this principle cuts both ways. If only combatants can execute military functions, only combatants can be targeted by military force.

Here, Mr. Putin’s disproportionate assault makes it impossible to apply discrimination appropriately. In combat, some amount of collateral damage is expected and justifiable. Shelling and bombing civilian population centers and threatening nuclear strikes do not meet the demands of this criteria.


Why should military officers care about this analysis? 

The signers of the Declaration of Independence knew their actions would be evaluated by “the Supreme Judge of the world.” The purpose of Just War Theory is to remind competent authorities of their unavoidable responsibility to uphold justice. It cannot be passed off or delegated. In his speech on 24 Feb, Mr. Putin said, “I want to emphasize again that all responsibility for the possible bloodshed will lie fully and wholly with the ruling Ukrainian regime.” Just War Theory, as received and understood by the modern world, demands that Mr. Putin is responsible to satisfy each criterion. No actions of his enemies can abrogate his responsibilities or exonerate his own behavior in going to war or conducting it. He cannot wash his hands of this. The same is true for United States military officers executing their duties to advise civilian leadership and within the scope of their authority, to take military action. As Americans, we must be clear in our thinking and speaking as we “solemnly publish and declare” that Russia is unjust in her war as well as remain introspective in our assessment of United States Military action now and in the future.

Author’s Biography

Michael Robblee is an Active Duty Air Force Major currently serving on the Air Staff. He is a graduate of Air Command and Staff College where he earned a Masters of Art and Science in Military Operations. Michael also serves as an officer in his local congregation of the Orthodox Presbyterian Church. Michael and his wife, Darcy, live in Sterling, VA with their six children. Michael can be reached at

Disclaimer: The views expressed are those of the author and do not necessarily reflect the official policy or position of the Department of the Air Force or the U.S. Government.

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