No Such Thing as Christianity's Just War
Published: March 5, 2026 •
3 min read
What is the Christian idea of a “Just War”? Where did it come from? Spoiler: It’s not in the Bible.
It has its roots in history. Early Christians were mostly pacifists. Many early Christians refused military service, but things changed after the Roman Empire became Christian under Constantine the Great. Suddenly, Christians weren’t just victims—they were rulers and had to govern, defend borders, and maintain order.
Rulers then tried to reconcile Jesus’ teachings on peace and love with the reality that governments sometimes need to use force. They were trying to justify state violence without abandoning Christian ethics.It's easy to understand why there was a need for this concept, but was creating the idea of a Just War a good idea? Well, if you know anything about history, clearly the answer is no. All it did was open the door for governments to find a "just cause" and slaughter millions, waging war in the name of God. And it is still happening today.
The Trump administration, like ones before it, has invoked the idea of a Just War in relation to invading Iran.But is it? What is a Just War? Traditionally, it has to meet these criteria:
- There is a just cause (self-defense)
- It has right intention (not revenge, conquest, etc.)
- It’s a last resort
- There is a reasonable chance of success
- The response is proportional
- Civilians must not be targeted
The Trump administration says it believes the war with Iran fills all these requirements...a claim that is, at best, very shaky. I believe a better argument could be made that only one, "there is a reasonable chance of success", is being fulfilled in invading Iran. And, as of this writing, that is in question too.
But even if the administration could make a convincing argument that everyone would believe, that invading Iran was a Just War, it is beside the point.. Why? Because the idea of a Just War is a HUMAN concept, not in the Bible, and goes against a mountain of non-violent commandments by God and Jesus alike.There are passages in the Bible that people use to support the idea of a Just War like "Governments bear the sword to punish wrongdoing" (Romans 13). But, as you can see, that says governments, not Christians. Of course anyone can point to the Old Testament wars as evidence of war being permissible. But those were overseen by God Himself. Who would place themselves in the position of God and declare war?
If there were such a war that could be permissible, then an argument could be made that World War II was one. Stopping world powers from invading and taking over, saving millions of lives, and putting the world back into a place from which peace might grow seems just. But invading a country which cannot attack us, more likely for resources than for any righteous cause, sounds more like an Axis power than a holy one.
I don’t believe anyone truly thinks Iran has nuclear weapons.
