Basics of Christian Just War Theory

In the comments section to a previous post, somebody asked if there are any studies on just war theory (JWT) that the hosts of this site recommend. I give some references at the end, but will also take this opportunity to remind everyone about the principles of just war.

Basic Principles of Christian Just War

jus ad bellum

(1) The cause and intention of a war must be just. The war must have limited objectives that are just in the eyes of God. This includes protecting the innocent who are threatened or restoring order in the society. Wars of conquest or wars to “spread democracy” are thus unjust.

(2) In a just war there must be a right to intervene with violence.

(3) There must be a declaration of war by lawful authorities.

(4) In a just war, war is the last resort. Even if a nation has a just cause and a right to intervene, it must not engage in warfare unless it is the last resort. An appeal must first be made to right before recourse is made to might.

(5) A war is just only if it is entered into with a probability of success. Not all just causes can be successfully prosecuted. It is unjust to ask for vain sacrifice.

jus in bello

(6) A just war is one where the cost that is to be incurred is not thought to be a greater evil than that which is to be remedied.

(7) The means of a just war must be both discriminative and proportional. Total war is unbiblical. A just war is one which carefully distinguishes civilians from combatants. Wars should not be needlessly destructive. The violence used must only be sufficient to restore the peace that has been destroyed by the aggressor nation.

Advocates of Just War Theory

Augustine is the “father” of just war theory, but his thoughts on the subject are dispersed throughout his vast corpus. Aquinas systematized them in the ST. The pertinent section is found here.

The Westminster Standards demand JWT, although it does not articulate the details (see WCF 23:2 and WLC Q. 136). Almost all Reformed theologians have advocated JWT, which invariably amounts to defensive war. If there are exceptions, I am ignorant of them.

Calvin: Institutes, book 4, sections 11 and 12.

Turretin: Institutes, Topic 11, Question 17.

Dabney: Lectures in Systematic Theology, Lecture 33, Question 7.

Charles Hodge: Systematic Theology, Part 3, Chapter 19, Section 10.

John Murray: Principles of Conduct, pp. 178-9.

Greg Bahnsen did a nice series on JWT called “A Christian View of War,” available from Covenant Media Foundation.

19 thoughts on “Basics of Christian Just War Theory

  1. I think #2 needs further elucidation. As it stands it is a tautology (just and right are synonymous). I think the second point has better been stated as possessing “right intention”, i.e, not for self-interest or aggrandizement. But there are problems in sorting this out. To quote,”At what point does right intention separate itself from self-interest? On the one hand, if the only method to secure peace is to annex a belligerent neighbor’s territory, political aggrandizement is intimately connected with the proper intention of maintaining the peace. On the other hand, a nation may possess just cause to defend an oppressed group, and may rightly argue that the proper intention is to secure their freedom, yet such a war may justly be deemed too expensive or too difficult to wage; i.e., it is not ultimately in their self-interest to fight the just war.” Internet Encyclopedia of Philosophy.

    I think each point must be weighed and balanced against the others. I think it is easiest to see that, apart from national Israel in the O.T., just war theory rests on the right to self-defense as a notable exception to the 6th commandment, thou shalt not kill.

  2. Is there any war that Turretfan or you see as fitting this criteria that you can say is justified?
    I’m just curious

  3. “The cause and intention of a war must be just. The war must have limited objections and objectives that are just in the eyes of God.”

    1. How is the intent of Congress to be determined?

    2. By whom or by what is “limited” to be determined?

    [Preface to Question 3: I think the religion of Islam is inspired by Satan.]

    3. Does not this phraseology justify, in their own eyes, the efforts of Islamofascists?

    Thanks M.A.B. for the heads-up.

  4. “Almost all Reformed theologians have advocated JWT, which invariably amounts to defensive war.”

    Mr. Butler – great topic and article. Considering the quote above, would you affirm (like Bahnsen) that a just war must be defensive? I would myself but I didn’t see this explicitly stated above.

  5. Jimmy Li,

    Whether any recent wars are “just” under the seven-part test above is a great question.

    I’m not ready to give a full answer yet. In part that is because I am still in the process of rethinking my own view of JWT in view of MRB’s systematic post. In part that is because I haven’t yet fully convinced myself that all seven points are correct. And in part that is because there are so many wars to pick.

    As to the current unpleasantness in the Gulf region, at least arguably:
    (3) is met – Congress did kind of declare war (although I think strict Constitutionalists would be troubled by HOW they did so);
    (5) is met – We did destroy the regime we set out to destroy, and we knew we would do so quickly and relatively easily;
    (6) is met – at least if Bush is the one who gets to weigh the costs vs. evil (i.e. if he is the “thinker” in item (6); and
    (7) is met – the war falls far short of total war, and the military forces generally limit their action (under threat of court martial) to proportional means.

    I suspect that the authors/owners of First Word would take the position that 1, 2, and 4 are not met. Perhaps they would also dispute some of the items I list as arguable above.

    There are certainly some who would take the view that 1 and 2 are met (though that would be much more hotly debated here, I suspect).

    I doubt anyone but the most sycophantic supporter of Bush would say that (4) was literally met.


  6. If Reformed Christians believe there was a just cause for our aggressive invasion of Iraq, then I have just one question. Which nation before the courts of God, deserves more so to be judged by invasion of a foreign military power, occupied by same and then the invaders attempt to establish a new government (in their image) by force in this land of their conquest? Should it be the one with a single ruler who is alleged to have tyrannized and murdered 10,000 of his citizens? Or should it be the aggressor nation where 30% of their very people are willing to bloody murder their own pre-born children while the rest of the population effectively stands idly by doing nothing and all the while their citizenry-elected government legalizes/encourages/funds this slaughter – totaling 50 million children?

    If such a weak standard justifies our action in Iraq then where are the invaders getting prepared to invade us, with evangelical cheerleaders and all?

    The functional antinomianism alive in the Reformed and broader evangelical world, coupled with the positive financial sanctions bestowed upon the church by this same murderous govt., thrown in with a dash of personal cowardice and spiced with a tad of self-delusion – makes it all interesting sport to consider some speck in Iraq’s eye, while we ignore the Redwoods in our own. A bit of honest reflection and humility would require us not to be involved with any such invasion. I often wonder how much the ongoing evangelical support of Iraq really serves as an distraction from our own massive national crimes (where abortion and perversion are just the beginning) and a delusion for us to play at public “righteousness”.

  7. PDorr,
    * Do you think that those Reformed Christians who view the war as just think that it was just because they think that America is sinless?
    * Do you think that those Reformed Christians who view the war as just think that America is not ripe for judgment from God for its sins?
    * If America were as righteous as humanly possible, would that change your outlook on the war?

    I think the answer to each of those questions is “no.” But, to be frank, I have not seen any Reformed apology (defense) for the war. So perhaps this is all academic.

  8. Eliza – Yes, each point needs elaboration. My aim was to give the theory in skeletal form. And, yes, JWT is in many ways an extension of the right to self-defense.

    M.A.B. – I’m not sure what subtitle you are referring to, but I fear it was the typo in the original.

    Jimmy Li – Two, maybe three, just wars have been waged by American governments since 1776. The First War for Independence, of course, the War of 1812 (perhaps), and the Second War for Independence. One of the many evil consequences of losing the last one on the list has been a history of imperialist crusade-type wars.

    JC –

    “1. How is the intent of Congress to be determined?”

    A declaration of war is what the Constitution says. That’s good enough for me.

    2. “By whom or by what is “limited” to be determined?”

    The law of God, of course. Deuteronomy 20 is the best place to start. Remember, though, that we must discern the general principles of this text from the particular ones.

    “[Preface to Question 3: I think the religion of Islam is inspired by Satan.]”

    I will accept your preface and add that every other non-Christian religion is inspired by Satan, with Judaism being the example par excellence. Agreed?

    “3. Does not this phraseology justify, in their own eyes, the efforts of Islamofascists?”

    (1) The term, “Islamofascist” lacks coherent meaning.

    (2) I’m not familiar enough with Islamic ethics to answer this question. I do know that they have some theory about just war. And while I am sure it would turn out to be deficient, I am also sure that it is not the absurd caricature painted by neo-con war-mongers

    Josh – Yes, a just war is a defensive war.

    TF – The current wars fail on all counts with the possible exception of (5). I say possibly (5) not because of the definition of success de jour (how many have there been? I’ve lost count), but because the real terms of success are U.S.-British-Israeli hegemony in the Middle East, control of the oil reserves, preservation of the U.S. petrodollar, division of Iraq into three weak states, and control of central Asia which the Cryptocracy views as the center of the global game board. On these terms, one can argue that the wars have been a great success.

  9. Thank you Michael for answering
    I’m going to chew on this, I don’t want to aggregate all over the internet world misguided and not well thought out opinions

  10. MRB,

    Obviously you have only billed this as “the Basics.” Nevertheless, I have an enhancement proposal, should you consider racheting the article up to the next notch.

    I notice that in the comments on another post, you describe some proposals for remedying an unjust war.

    Clearly you’ve given some thought to how we should go about remedying what you very strongly believe is an unjust war.

    A complete theory of just war would, I submit also include a “remedies,” section. It appears that your proposed remedies are designed to equate to restitution.

    Perhaps, for this “basics” level discussion, a single concept:

    B) A nation that engages in unjust war against another nation should restore the offended-against nation as nearly as possible to its original condition.

    might be fitting as an addition to the prohibition in what would be (A) (i.e.(1)-(7)). That, of course, assumes that your intent was to apply a principle of restoration and not to try to parallel the punishments meted out to Germany by the nations that defeated it.


  11. TF –

    Restoration is indeed necessary when a crime has been committed. I don’t think this needs to be included in our theory of just war, though.

    And, yes, it is restoration. My proposals are not at all meant to be a Versailles-style reprisal for real or perceived wrongs.

  12. Dear MRB,

    Perhaps you have thought this through better than I have. My rationale for suggesting identification of the appropriate remedies for unjust war is because not all crimes are treated the same in the Law.

    Crimes of murder, rape, and kidnapping (at least two – and quite often all three – of which arguably happen in most unjust wars) are properly remedied by death of the criminal, not restitution/restoration.

    Crimes of mayhem (also virtually always occuring in an unjust war) are remedied by corresponding retribution.

    It seems to be that only crimes of theft, willful negligence are remedied by restitution (which is not simple restoration).

    Assuming there is such a thing as an unjust war – the two subsequent questions are:
    * is an unjust war also a crime?
    * what is the appropriate remedy for the crime?

    You seem to view unjust war as analogous – at least for remedial purposes – to theft. It certainly seems to be an important question to me, but perhaps you have a more thoughtful (than my own) reason for excluding discussion of remedies from the basics.

    Would you also exclude the discussion of remedies from a more complete discussion of unjust war theory?


  13. TurretinFan:

    * Do you think that those Reformed Christians who view the war as just think that it was just because they think that America is sinless?

    No, but that distracts from the point. If their often myopic application of Just War principle re: Iraq was applied to this country with equal vigor, then they should be calling out from the public square for some nation more righteous than us to invade us. We, as a once Christian nation (as defined by our previous public laws and treaties), are more culpable then a Muslim nation as well. Again, I think they enjoy the sport and the distraction it provides.

    * Do you think that those Reformed Christians who view the war as just think that America is not ripe for judgment from God for its sins?

    If they do think we are ripe for judgment then again, why aren’t they applying their view of “just” war to ourselves and openly calling for some foreign power to invade us and put a stop to the mass murder of the children of this country? After all, in early 2003 we were told of those Iraqis crying out for our help and that they’d be cheering us in the streets when we arrived. I’m waiting to greet in the streets the invading army which comes to shut down the mass murder of America’s children. Meanwhile, with all generation IV tactical war issues aside, we’d do good to consider if the consequences of Achan’s sin (Joshua 7) may be what we are seeing applied in our day to the grinding halt of our “mighty” military in Iraq. By public law, we have far too many accursed things among us.

    * If America were as righteous as humanly possible, would that change your outlook on the war?

    If America were as “righteous as humanly possible” there wouldn’t be this war in Iraq.

    I think the answer to each of those questions is “no.”

    But, to be frank, I have not seen any Reformed apology (defense) for the war. So perhaps this is all academic.

    Not academic at all. Real continental and presbyterian reformed young men are joining up and going off to this unjust war with the consent of their fathers and elders. These young men are seen as those coming from a nation whose foreign policy has for decades created, funded and aggravated these tinderboxes.



  14. I think it follows from these principles that the US policy (since U.S. Grant) of “unconditional surrender” is evil.

  15. “Basics of Christian Just War Theory.”

    It is most interesting to see the use of the term: “Christian Just War Theory.”

    On what basis are the above principles reckoned “Christian”?

    Since ‘Christian’ necessitates/presumes the presence or will of Christ, I am wondering to which of Christ’s teaching/s the JWT conforms?

    For my recollection of Jesus’ teachings disappoints handsomely: not once did I read where He declared war; of any human fabrication.

    Jesus’ presence on earth was a sign of spiritual warfare. His presence among us thus sounded the death knell for satan, which soundly indicates to me that His (Jesus’) war was one of spiritual proportions, with scope and implications far exceeding mortal affairs and the realm in which war, (as humans understand it), is fought by humans.

    Thus, Jesus’ coming can be interpreted as an initiating pulse to actively engage in spiritual warfare. This war is not fought with weapons fashioned by human pride and arrogance. Rather, as Paul says, “3For though we live in the world, we do not wage war as the world does. 4The weapons we fight with are not the weapons of the world. On the contrary, they have divine power to demolish strongholds.” (2 Corinthians 10:3,4). AND~

    “…with weapons of righteousness in the right hand and in the left.” (2 Corinthians 6:7).

    Then perhaps it can be fathomed that the only Christian just war is one that is spiritual? Since it is the only one supported by orthodox (ie., universally applicable/universally perceived) Christian doctrine.


  16. Mitchell (#18) — We could go one of two directions here: a detailed exegesis of the specific passages you mention; or unpacking the hermeneutical frameworks that separate us.

    I suggest the latter is the key difference between us. “Christian” for you means “the presence or will of Christ” qua Jesus’ words, or at most the NT; whereas for us, the will of Christ is revealed in all of Scripture.

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