See also Vattel (_Law of Nations_, II. Ch. XVIII. § 332):—“But if anyone would rob a nation of one of her essential rights, or a right without which she could not hope to support her national existence,—if an ambitious neighbour threatens the liberty of a republic, if he attempts to subjugate and enslave her,—she will take counsel only from her own courage. She will not even attempt the method of conferences, in the case of a contention so odious as this. She will, in such a quarrel, exert her utmost efforts, exhaust every resource and lavish her blood to the last drop if necessary. To listen to the slightest proposal in a matter of this kind is to risk everything.” But, indeed, looking away from questions so vital and on which there can be little difference of opinion, we are apt to forget, when we allow ourselves to talk extravagantly of the future of arbitration, that every nation thinks, or at least pretends to think, that it is in the right in every dispute in which it appears (cf. Kant: _Perpetual Peace_, p. 120.): and, as a matter of history, there has never been a conflict between civilised states in which an appeal to this “right” on the part of each has not been made. We talk glibly of the right and wrong of this question or of that, of the justice of this war, the iniquity of that. But what do these terms really mean? _Do_ we know, in spite of the labour which has been spent on this question by the older publicists, which are the causes that justify a war? Is it not true that the same war might be just in one set of circumstances and unjust in another? Practically all writers on this subject, exclusive of those who apply the biblical doctrine of non-resistance, agree in admitting that a nation is justified in defending its own existence or independence, that this is even a moral duty as it is a fundamental right of a state. Many, especially the older writers, make the confident assertion that all wars of defence are just. But will this serve as a standard? Gibbon tells us somewhere, that Livy asserts that the Romans conquered the world in self-defence. The distinction between wars of aggression and defence is one very difficult to draw. The cause of a nation which waits to be actually attacked is often lost: the critical moment in its defence may be past. The essence of a state’s defensive power may lie in a readiness to strike the first blow, or its whole interests may be bound up in the necessity of fighting the matter out in its enemy’s country, rather than at home. It is not in the strictly military interpretation of the term “defensive”, but in its wider ethical and political sense that we can speak of wars of defence as just. But, indeed, we cannot judge these questions abstractly. Where a war is necessary, it matters very little whether it is just or not. Only the judgment of history can finally decide; and generally it seems at the time that both parties have something of right on their