What Is A Just War?

The parish Q&A box provides me and my staff colleagues with a lot of food for thought. We’re limited to 450 words of response, so I was a little concerned when I drew this two-parter, and its companion below. This answer, in slightly edited form, will appear in the parish bulletin this weekend. I started by summarizing CCC 2309 and moved on from there:

The Catechism of the Catholic Church summarizes four conditions which must be met in the traditional doctrine of “just war.”

  1. The damage inflicted by the aggressor … must be lasting, grave, and certain.
  2. All other means (of ending conflict) must have been shown to be impractical or ineffective.
  3. There must be serious prospects of success.
  4. (The “justified” side) cannot produce evils and disorders graver than the evil to be eliminated.

Is modern warfare always immoral?

Some say yes. Pacifists would delete “modern” from the question and also answer in the affirmative. On the other hand some apologists for legitimate defense would suggest “everything has changed,” and that the rules of waging war must themselves be changed.

The Church uses strong language in urging responsibility on the part of leaders who wage war. The word “rigorous” is used to describe the application of the principles of “just war.” Some modern conflicts, like last century’s Cold War, or this century’s War on Terrorism, seem to slip the bounds of what war looked like in the centuries when the Church formulated principles of “just war.” It might be argued that the threat behind public rhetoric from a terrorist is less certain, say, than an army massing itself outside a castle wall with catapults and crossbows.

For a superpower, if the nuclear option escalates killing, especially the targeting of civilians, would that mean just war principle #4 is violated, and therefore any nuclear strike against civilians is immoral?

As large countries consider action against smaller foes, are we forced to consider that without the options of indiscriminate action against civilian targets (our bigger, better bombs), do our wars have serious prospects of success? We might be annoyed with a petty dictator who uses YouTube to lob insults from far away. But principle #3 holds us to a high standard: if we’re going after someone, we have to have a reasonable chance of success to eliminate the evil.

Rather than pluck out particular principles about war, my suggestion is to begin with the Catechism, 2302-2317 and read the entire section “Safeguarding Peace.” From there, check the Vatican II document Gaudium et Spes sections 77-82 which summarize church teaching on “The Fostering of Peace.” And if the issue is a serious one for you personally, I suggest you read broadly among legitimate pacifists like Dorothy Day or Daniel Berrigan, from the middle path in the widely available commentaries of the popes, John Paul II and Benedict XVI, as well as Catholic authors like George Weigel or Michael Novak who try to make the case that terrorists place us in situations in which “just war” principles are outdated or even dangerous.

Let us know if you come up with any great answers in your search. The world, no doubt, needs you.

About catholicsensibility

Todd lives in the Pacific Northwest, serving a Catholic parish as a lay minister.
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2 Responses to What Is A Just War?

  1. John Donaghy says:


    I would urge people to look first at the US bishops’ pastoral letter of 1983, The Challenge of Peace. It has a better section on this than the Catechism. I’d suggest paragraphs 27 to 121.

    The bishops also released a 1993 short statement, The harvest of justice is sown in peace, that has a shorter description of Catholic teaching on war and peace that places the issue in the context of theology and spirituality and not merely in terms of ethics.

    These two texts are, I think, classics – not that I agree with all the documents say – but they say it with some clarity and speak to the US. they both can be found on line.

    I find the Catechism’s treatment truncated.
    Also, the St. Thomas library has a good collection of books on Catholic teaching on war and peace.

    One book that I would recommend is by a Mennonite pacifist who taught for a long while at Notre Dame. John Howard Yoder’s “When War Is Unjust: Being Honest in Just-War Thinking” is a good commentary on the issue which takes Catholic thought seriously. At least one edition had a long essay by a Catholic moral theologian.

    As for books on nonviolence, I’d recommend Thomas Merton who has some great essays in “Passion for Peace: the social essays” and “Peace in the Post-Christian Era.”

    For a history of Catholic thought, written by a pacifist, try Eileen Egan, “Peace Be With You: Justified Warfare or the Way of Nonviolence.”

  2. Todd says:


    Thanks for the suggestions. I rewrote it a bit to include them as Barb was having trouble fitting it all in anyway.

    Don’t know why I forgot about the peace pastoral. I actually have two copies on my bookshelf here.

    I like Eileen Egan; I think I will look up her book.

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