It is often the case that we ought to avoid war – because it is unpredictable, highly destructive. That’s why we should always seek peaceful means of resolving conflict. But even if there’s an injustice we can’t remove by peaceful means, sometimes an injustice is better borne than opposed by force of arms. So that’s why the basic criterion of just war is grave injustice. Now, we can argue what’s grave and what’s not but, yes, some injustice should be borne in order to avoid the hazards and costs of war.
On the other hand, we need to be honest here that peace has its hazards and its costs too. It is true that we didn’t go to war in 1994 to save the Tutsis from the Hutu. That’s true, and so we stayed at peace – but we mustn’t forget. the Tutsi didn’t stay at peace. They got slaughtered. So peace isn’t simple. We didn’t take up arms to stop Germany reoccupying the Ruhr in ’36. We thought we’d tolerate that. Well, there’s an argument that that therefore encouraged Hitler to become more bold. At the time, it looked like a prudent move; in retrospect it may have been imprudent. So peace has its risks, and peace also has its costs. So we have to consider both.
In the end, it’s very difficult, I think, to weigh up costs and benefits. I mean, most Anglo-Saxons, whenever I ask for a show of hands in Ireland or England on this topic, do you think that the Allies were right to prosecute the war against Hitler in 1939-1945? 90 percent of hands go up. Well, on the one hand, regime change in Berlin was a very good thing, and we all know why. It wasn’t just that we stopped the Holocaust, it was all sorts of other people were saved from being slaughtered and the regime was a very, very vicious one.
On the other hand, that did cost us, or the world, somewhere between 60 and 80 million human deaths. Europe was devastated. Atomic bombs were used. Now, I don’t know of any way of weighing those up. It’s very difficult. Was it worth it? Very difficult to answer that. I think all I can say is, sometimes there are regimes that are so evil they have to be stopped, because long term we just can’t tolerate them. But in advance, we don’t know what it’s going to cost.