Again the Pope says that the just-war tradition is outdated. And again I ask: What’s the alternative?

“The theory of a just war dates back to centuries when it was impossible to imagine the weapons and the destructive capacity available to humanity today,” Pope Leo told journalists on his flight to Spain.

True. The just-war tradition dates back at least to St. Augustine, although its roots can be traced further (to Cicero, for instance). Those ancient origins don’t make it irrelevant. The commandment, “Thou shalt not kill,” is even older.

In fact the just-war tradition is a series of reflections on how to reconcile that commandment with the requirements of self-defense, in this case the defense of a nation. That question doesn’t go away when weapons become more powerful; it only becomes more important.

If you accept the idea that a nation has the right (and duty?) to defend itself— as the Pope does, and the Catechism does, and the Catholic moral tradition does— then you’re forced to think about when and how that defense is morally licit. And if you do— congratulations!— you’ve just joined in the discussion of justice in warfare.

So the question is not whether or not to eliminate just-war thinking; you can’t do that. The question is whether you want to discard all the thinking that has already been done on the subject, or learn from the wisdom of previous generations.

Does the just-war tradition need to be updated? Sure; always.