It is no coincidence that the just war tradition was invented around the time that the Emperor Constantine decided to baptise the Roman empire as Christian. The fact that many Christians had often been pacifists was something of an embarrassment to the head of the largest war machine the world had ever known. So just war was itself created to allow the Roman army to keep on fighting. Those theologians who came up with it were no doubt well-minded, but they were little more than the “useful idiots” of the military complex.