Just War: Considerations for Christians. A Series of Reflections: No. 2 - A Critique of Just War Theory, by Dana S. Grubb


The Just War Theory is a set of criteria used by some Christian churches (e.g., Roman Catholic and Episcopal) to determine whether or not it is morally appropriate for Christians to support and/or to directly participate in a particular war. 

In the early Christian Church, the bishops forbade Christians from joining or staying in the Roman Army. Prior to 180 CE, there is no record of Christians being in the Roman Army. In 180 CE, records indicate that there were a few Christian soldiers. Their numbers increased considerably in subsequent years.  

Until about 400 CE, Christian bishops appear to have focused their opposition to Christians being in the Roman Army on the paganism inherent in the life of Roman soldiers. Christians were not supposed to be offering incense to the pagan gods, which was required upon enlistment and usually on daily basis thereafter. These pagan rites appear to be linked to the absolute loyalty and obedience required of Roman soldiers. 

It is not clear from the bishops’ writings whether or not the Roman Army’s wars were also a major factor in the bishop’s decision. However, a literal reading of the Sermon on the Mount, etc. imply that any killing of another human being is forbidden.

Around 400 CE, various foreign armies were seriously threatening to conquer all of the western part of the Roman Empire, including Italy. At that time, St. Augustine introduced the idea that it might be morally permissible for Christians to fight in some wars, though not in all wars. 

In the Middle Ages, church leaders developed a theory whereby a war could be justified only if certain criteria were met. Initially, this provided a moral justification for Christians to remain true to their faith by not participating in a war. But over time, this became more of a justification for going to war, while still remaining true to their conscience.

In recent years, military officers and philosophers have entered the discussion. The military have their reasons for wanting a prohibition against the use of torture, poison gas, etc. However, they would want to be free to wage some wars, such as, World War II. 

During World War II, the U.S. initially the obeyed the international prohibition of the bombardment of undefended cities. Unlike the British RAF, which routinely bombed entire German cities, the U.S. Army Air Force limited their bombing to industrial areas linked to war production. However, in the latter stages of that war, the Army Air Force switched from the daylight bombing of industrial areas of Germany to a general bombing of entire cities. In Japan, this resulted in the devastation of 67 Japanese cities, the firebombing of Tokyo, and the atomic bombing of Hiroshima and Nagasaki. 

During the Vietnam War, some Air Force pilots were so appalled by orders to napalm and fragmentation bomb Vietnamese villages that they refused to fly these missions. They were punished by career ending re-assignments.

Some Basic Flaws with the Just War Theory

As I will show, the Just War Theory is seriously flawed. Even if major changes are made, it is hard to see how it can be legitimately adapted to the rapid changes in technology, the fighting methods of various war-making groups, and various other flaws.

First, the Just War criteria cannot be reliably evaluated before a war or even during the early stages of a war, because governments routinely conceal much of the truth. Even national leaders themselves are usually wrong about such matters as the outcome, duration and aftereffects of a war, as they are seldom assessable in advance. It has been said that “Truth is the first casualty of war.”

Second, war technology and the political aspects of war are rapidly changing. For example, the cost of developing drone weapons is dropping so fast that even relatively small nations are likely to soon be able manufacture and even supply them to insurrectionists in another nation.

Third, the massive level of slaughter in war is so large as to make it hard to reconcile with the good sought by a war. The Vietnam War was publicly estimated to have cost at least a million deaths in population of about 25 million people. 

Fourth, it cannot deal with such basic moral issues as the Army’s conditioning of young recruits to have the absolute and instinctive obedience to military orders required for having an army rather than just a group of warriors (e.g., the U.S. Cavalry vs. native American Indians). This level of obedience means giving the military and/or nation a status that is equal to or even above that expected for God. This would be a violation of the First Commandment. 

Fifth, Jesus’s teaching on love for one’s enemies. Israel was a client state of the Roman government and Roman soldiers were despised by the Jews. Jews were not subject to Roman military conscription and were not wanted for the military. Thus, military service was not an option for Jews. Hence, Jesus had no reason to explicitly deal with military service. 

However, Jesus did teach that we should: “Love your enemies and pray for those who persecute you” Matthew 5:8. Jesus also demonstrated his love for the hated Romans by healing the son of a Roman centurion. Matthew 8:5. A literal reading of the Sermon on the Mount, etc. would not only rule out killing in self-defense, but even more surely the mass slaughter of war.  

Sixth, the conduct of war presents such moral problems to the soldiers involved that some have described the experience as “soul injury.” Apart from religion, there seems to be an inherent taboo on killing one’s own species.

Specific Criticism of Just War Criteria

We have listed here: the titles for the criteria for a Just War; a very brief statement of what it means; and some of the problems encountered when attempting to use the criteria to determine whether a particular war can be considered justified or not. 

The Just War theory is divided into three phases:

Just Cause; Just Conduct; and Just End of War.

Problems with the Just Cause Criteria

Legitimate Authority

A national government or similar authority (e.g., U.N.) An internal revolution would not count. However, if the German Army had had a coup against the Hitler government in 1943, what should have happened then? Does the German military become the legitimate government? Who decides?

Just Cause:

A war must be against a serious public wrong (e.g., to prevent annexation of one’s land; to stop a genocide against Jews; etc.). However, it is easy for a national government to invent a just cause to generate support for initiating a war.

Right Intention:

Leaders must be motivated by a national goal that makes that makes the war just, and not by some other goal such as annexing land or installing a puppet government. However, it is often easy for a government to frighten its citizens with unwarranted fears. For example, propaganda by the Hitler government of Germany that Poland was greatly increasing its military power and that he had to protect Germany by invading Poland. 


The war must be reasonably expected to do more good than harm. However, the high unpredictability of war, the power of modern weapons, and shifts in public support makes this very risky. With the Iraq War, our nation waged that war with overwhelming force. As cited by the New York, “What followed has been years of violence, countless deaths in the region and the hemorrhaging of funds to support the war effort.” 

Probability of Success

The war must have a reasonable chance for victory. In South Vietnam, the U.S. had a huge field army on the ground and complete control in the air. Short of using nuclear weapons, the U.S. was unable to win. As noted by the British historian, John Keegan, the course of a war is rarely what was predicted.

Last Resort

War must not be used until the other options have been have been found to be ineffective or impractical. The usual alternative has been economic sanctions. While these have a minor effect on the wealthy, they can have harsh consequences for the poor. Examples are North Korea and Gaza.  

Problems with the Just Conduct Criteria


Military forces must not attack non-combatants. The bombing of cities, towns or residential areas is forbidden. The criterion is a good one. However, it is widely disregarded. In World War II, both Germany and Great Britain routine bombed entire cities. When it was bombing in Europe, our nation began by avoided the bombing of cities, except for those areas in a city that had war production industries. However, this ended when the U.S. joined the British Royal Air Force (RAF) in a very deadly bombing of the entire city of Dresden. With Japan, the U.S. bombers did a massive bombing of Tokyo with incendiary bombs with the intent of creating a fire storm that killed huge numbers of civilians. This was followed by nuclear bombs dropped on two Japanese cities.


The harm to be done must not exceed the goal sought and the military use of the force used must also be the minimum force needed. However, it is not possible to know in advance how large a force will be needed. For example, in the initial stages of the U.S. involvement in the Vietnam War, it was thought that U.S. military aid and military advisers might be enough. It was then thought that one or two army divisions would work. Eventually, a huge field army with massive air power was used. Eventually, the war had to be abandoned. The result was a de facto defeat.

Military Necessity:

A military attack must be focused entirely on defeating the enemy’s forces. It must not have other objectives, such as, genocide or land annexation. This may be blurred if military personnel are (or alleged to be) mixed in with civilians or if weapons are (or alleged to be) stored in schools or hospitals.  

Fair Treatment of Prisoners

Prisoners of war have basic human rights that must not be violated. These include housing, food, clean water, medical care, etc. There must be no waterboarding, sleep deprivation, solitary confinement or other types of torture. However, some authorities persist in the belief that torture produces useful military information. There have also been incidences of a nation re-defining torture to allow such techniques as waterboarding.

No Evil Methods Used

There must be no use of biological weapons; no mass rape of women and girls; etc. Biological weapons and poison gas cannot be used without endangering both sides, so they are not normally used anyway. 

Problems with the Just End of War Criteria

Status of rights before war:

The end of a war should be followed by a restoration of property rights and human rights as existed before the war. When World War II ended in Europe, the Marshall Plan was a positive exception to the usual rule of doing nothing.

Punishment for war crimes: 

Political leaders and commanders on either side who were guilty of war crimes should be tried and punished for their crimes. However, when the winners run the trials, it is likely that only criminals on the losing side will be punished. The Nuremburg war crimes trials punished German war criminals, but did not punish allied war criminals. For example, the British leaders responsible for the firebombing of entire German cities were not punished. 

Peace treaties

A peace treaty must fair to both sides if it is to work. If either side believes that the treaty is grossly unfair, future conflicts are likely as occurred with Germany after World War I. (German perceptions may have been unrealistic, since the majority of the fighting occurred in France and retreating German forces destroyed French manufacturing facilities in their retreat.)

Compensation for VictimsInnocent victims of the war should  be compensated to the extent that it is possible to do so. Germany provided some compensation to Jewish families who lost family members due to the Nazi Holocaust during World War Two. [These last four criteria are from the Ethics Center and the four examples are by the author.]



Center on Conscience and War (CCW), 1-800-379-2679. The CCW office is at 1830 Connecticut Avenue, N.W., Washington, D.C. 20008. CCW assists members of the military who have become COs; young people who are considering joining the military (with information); and expert assistance for those making CO claims, etc.

The Episcopal Church’s resources are available on the Internet at www.episcopalchurch.org and include: the EPF pamphlet “Cross Before Flag” (as of 2005); the Church’s “Conscientious Objector Packet,” and, for those who wish to be listed with the Church as COs, the opportunity to be listed on the Church’s “Conscientious Objector Registry.” To get the above material on the Church’s website, select: “Young Adult and Campus Ministries.” Then select “Conscientious Objector Registry” for the above resources.

 The Ethics Center – https://ethics.org.au, 2016. Secular.

 The Face of Battle, John Keegan, 1976. What war is like and how war seldom produces the expected outcome.

  The Just War Tradition – An Introduction, David D. Corey and J. Daryl Charles, 2018. A good book by secular scholars.

  Morality and War, David Fisher, 2011. An excellent book by a military scholar.

  The Morality of Killing in Self Defense: A Christian Perspective, Jonathon Spelman, 2008, Ashbrook Statesmanship Thesis. Based on the Old and New Testaments and St. Augustine’s writings (circa year 400 C.E.).

  Thinking Faith – http://www.thinkingfaith.org/articles.  Roman Catholic.

  Wikipedia - http://en.wikipedia.org/wiki/Just_war-theory  

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