How Can War Ever Be Justified?

In a just war, there is some legitimate self-defense or some legitimate defense of another who needs our help against an aggressor. And this defense is sanctioned by some legitimate authority that has care of the whole community. These are actions that are intrinsically good, not evil. To be sure, such defense can lead to actions that cause some physical evil in order to prevent an injustice, but this is often necessary. Thus, to kill someone who is attacking innocent people is not murder. Even Our Lord resorted to violence to correct the moneychangers in the temple, and I’m sure the whip he wielded hurt!