A reader writes:

I am a long time reader and fan of yours.  The other day one of my friends posted on facebook that he couldn’t find a prohibition on pre-emptive war in Church teaching, and therefore didn’t think it was always wrong.  I went to the Catechism and did a search at Catholic Answers to try to find the teaching, and I haven’t found it yet.  I imagine it is in an encyclical or two, I was hoping you could point me in the right direction of where to find this teaching.

Some time ago I wrote piece about the Semi-Permeable Membranes of the Various Protestantisms.  The point of the piece was that there is a peculiar game played in order to maintain rejection of Catholic teaching in Protestant circles.  It goes like this:

1. If a thing is condemned by the Church, but permitted by the Protestant (say, gay marriage) the demand is for an explicit text forbidding it (“Show me where Jesus said one word about not allowing gay marriage! That’s just the Church imposing its purely human ideas on what Jesus came to say.”).
 
2. Conversely, if a thing is allowed by the Church but condemned by the Protestant, the demand is for an explicit text commanding it. So, for instance, we get demands like, “Where in the Bible do you find anyone asking us to pray to dead people? That’s just the Church imposing it’s purely human ideas on what Jesus came to say.”

My reader’s friend is attempting Tactic 1 because he is looking for a way to justify something the Church plainly believes to be wrong.  How do I know the Church condemns pre-emptive war?  Because there is no room for pre-emptive war in the Church’s just war doctrine.  And that is so, because war kills innocent people and killing innocent people is bad according to the Fifth Commandment. 

The point is this: just war doctrine has been formulated by the Church, not to give us a trigger mechanism so that we can roll up our sleeves and commence slaughter with a song in our hearts, but in order to make it as hard as possible to go to war—because war kills innocent people.  The point of just war doctrine, in other words, is to set up a series of roadblocks to slow down and restrain the human appetite for mayhem, vengeance, murder and destruction which sinfully yearns for an excuse to be unleashed.  Just war doctrine is formulated in such a way that you have to fulfill all the requirements of just war teaching, not just one or two, in order to fight a just war.  The first requirement is that all just war must be an act of defense against an actual aggressor, not a preventative act of aggression against somebody you fear might be an aggressor one of these days.  Similarly, one of the criteria which must be fulfilled is that war must be a last, not a first, resort.  Therefore, pre-emptive war is necessarily unjust war—because war is not something you “get” to do.  War is something you tragically are forced to do as a last resort: like amputating your own leg.  Pre-emptive war, being neither a response to an actual act of aggression nor a last resort is, itself, an act of aggression.  It should be as morally desirable to Catholics as the thought of amputating one’s own healthy leg because you fear that in five years you might step on a nail and get gangrene.  Not too eager to do that?  Neither should any Catholic be eager to cut corners on just war doctrine—because war mean innocents will die, women will be made widows and children will be made orphans. That is why Joaquin Navarro-Valls, speaking on behalf of Pope John Paul II, said, “He who decides that all pacific means provided by the international law are exhausted, assumes a grave responsibility in front of God, in front of his own conscience and in front of history!”

In short, the argument that the silence of the Catechism on pre-emptive war is an argument in *favor* of it is like the argument that the silence of the Catechism on the subject of ritual cannibalism means that cooking and eating human beings in religious ceremonies is not “always wrong”.

Yes.  It is.  And so is pre-emptive war.  That’s why it’s not in the Catechism.