Does Just War Exist?

by Jon Kauffman

I am not convinced that it is possible for a Christian to fight a just war.

Aquinas’s conditions for a Just War – Jus Ad Bellum

  1. The war must have a just cause – eg against invasion, or for self-defence – and not to acquire wealth or power.
  2. The war must be declared and controlled by a proper authority, eg the state or ruler.
  3. The war must be fought to promote good or avoid evil, with the aim of restoring peace and justice after the war is over.

Later conditions developed by other Christians – jus in bello

  1. The war must be a last resort when all peaceful solutions have been tried and failed, eg negotiation.
  2. The war should be fought with ‘proportionality’, with just enough force to achieve victory and only against legitimate targets, ie civilians should be protected.
  3. The good which is achieved by the war must be greater than the evil which led to the war.
An altarpiece in Ascoli Piceno, Italy, by Carlo Crivelli (15th century)
Thomas Aquinas, PD

Reasons I question the possibility of Just War.

  • I do not see anything in the teachings of Jesus that allow for Just War of violence by Christians.
  • I do not see anything in the teachings of the church prior to St. Ambrose that states Christians may be involved in violence.
  • The prophets such as Isaiah and Jeremiah began teaching a way foreshadowing non-violence.
  • How does a Christian soldier stop fighting if he finds out he in an unjust situation?
  • How does a Christian stop a war that does not meet the just war criteria of Aquinas?
  • If a countries foreign policy does not have a system to test each military endeavor to determine if it is a just war, can a Christian fight in such a military?
  • How is a war determined to be just by the US government?
  • Christians in Germany and Christians in Great Britain both thought they were fighting a just war in World War one. If both sides claim to have Just cause can both sides be following Jesus when they declare Just War?
  • Are we arrogant when we claim our side is right and God is protecting our country when we attack other Christian nations who think they are fighting a just war?
  • Osama Bin Laden in his letter to America after 9/11 talked about the decades of bombing of innocent people in the Middle East by the US and it’s allies. If he was fighting an invading enemy and thought God was on his side and would help him win, was he fighting a just war?
  • Some Christians claim that any war the United States fights is a just war. If we allow the government to make moral decisions for us, are we worshiping the government?
  • If we allow the government to protect us instead of trusting God for protection, are we worshiping the government?
  • If we support a government fighting an unjust war are we endangering our souls?
  • What do we do with the teachings of Jesus that contradict Aquinas’ just war theology?
  • When I was young I was tempted to join the military. I did not. When I start thinking about the answers to the above questions, I cannot come up with good reasons how a Christian could violently support any empire that has ever existed while following the teachings of Jesus.

Making arguments Taking Scripture Out of Context

Some Christians take Biblical passages out of context to justify violence. A few examples:

Romans 13.

Romans 13 says we are to be subject to the ruling authorities, however, Paul never gives permission to Christians to disobey God in order to be subject to the ruling authorities.

Paul says we cannot rebel against the authority: Consequently, whoever rebels against the authority is rebelling against what God has instituted, and those who do so will bring judgment on themselves. Romans 13:2.

Some Christians even use Romans 13 to justify wars such as the Revolutionary War. Paul was unjustly imprisoned by a repressive Roman government. The injustice of Great Britain against the American colonies was far less than the injustice St. Paul experienced from Rome. I believe the Revolutionary War was not just war in the eyes of St. Paul.

I am of the opinion we must read Romans 13 in the light of Romans 12. Is it possible to overcome evil with good when you are bombing innocent women and children?

Can a Christian fight in the military taking revenge for 9/11 and protecting America’s wealth and easy living and protecting oil wells owned by American companies?

I think we must also take these passages in context with Romans 8:28. God always brings about good for those who love him through the actions of evil men. We do not need to join in their evil activities.

For the first 3 centuries of Christianity, three times the Roman Empire tried to wipe out Christians like Hitler tried to wipe out Jews. These Christians remained faithful because God works for the good of those who love him through all things.

We can also compare the good that God brings when our enemies conquer us as compared to the good brought about through God using Babylon to bring about good for the Jews when they were taken captive and taken to Babylon.

God uses evil men to control the violence of evil men.

Matthew 8:5-13

Some Christians have mentioned to me that when Jesus healed the centurion’s servant, he was demonstrating that violence by Christians is acceptable. The centurion was an enemy soldier. It is possible the centurion was one of the soldiers involved in killing Jews on crosses, as was common at that time.

Rather than demonstrating that violence was acceptable, Jesus was showing us how to treat our enemy. Jesus healing the centurion’s servant is like an American Christian supplying Osama bin Laden with a dialysis machine in 2002. Or an American doctor helping a close adviser of Hitler during World War Two.

Jesus forgave a solider. If Jesus forgave an alcoholic, does that mean it is acceptable for the alcoholic to continue breaking God’s laws and continue his alcoholic ways?

Ephesians 6

Amazingly some have suggested that because Paul compared Christian service to military service that this means it is acceptable for Christians to use violence. In verse 12 Paul clearly says that our struggle is not against flesh and blood. And in 2 Corinthians 10:4, Paul says the weapons we fight with are not weapons of the world.

Ephesians 6 is showing us that fighting evil like Jesus fights evil is dangerous and we will suffer losses. Fighting for Jesus is a real war. More real than any war fought by the Kingdoms of this world. But we have the resurrection on our side.

When we sign up to fight for Jesus, we experience true freedom. It is a freedom that does not need a government to pamper us in our faith. Perhaps a Christian can live under a government-run by Boka Horam and die by the sword a few days later and have greater freedom than a Christian living in the United States.

Today completes the seventh year that I’ve been posting a daily picture on Twitter; I have yet to grow tired of the beauty around me. Picture: Copyright © 2020 by Leon Kauffman

Matthew 4:8-10

Some Christians claim that we as Christians have the responsibility to use violence if we are in government. Jesus passed the test of government of using government to further his Kingdom in Matthew 4. If Jesus did not use government, why should we? Why are we different than Jesus?


God demonstrates in the crossing of the Red Sea that he will fight for his children.

Throughout history, many Christians have been miraculously delivered from evil men. More Christians died for their faith in the 20th century than throughout all history before that.

Living as a nonviolent Christian is not safe in this world. But I would like to suggest that it is safer to be killed by our enemies when we are loving them than it is to live in the temporary freedom and wealth earned by killing our enemies.

Copyright © 2020 by Jon Kauffman. Permission to reprint in whole or in part is gladly granted when used to further the Kingdom of God. Permission is gladly given to re-blog this post.

Greatest Heresy of All Time? Just War Doctrine?

Reasons Christians Give to Say Violence by Christians is Legitimate

Jesus and the Roman Centurion, Matthew 8:5-13

All My Posts (Links)

Edited: 10/31/2021

Edited: 2/23/2022

Author: Jon

Jon Kauffman graduated from Goshen College, earning a BA in Religion. Jon attended a Mennonite Church while growing up and currently attends the Salvation Army Church. Jon works as a drafter at TrueNorth Steel, Fargo, ND.

2 thoughts on “Does Just War Exist?”

  1. My personal opinion is the fact that we are not animals just animals what separates us from them is the ability to negotiate and talk about a situation it should be able to be resolved that way we are human God men we are not just man the animal any longer


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