The preamble to the Protocol asserts that a war of aggression is an international crime. I have discussed above[1] the agreement of the parties to the Protocol not to resort to war except in defence against aggression or in aid of defence against aggression or perhaps in execution of a judicial decision or arbitral award. This is the general covenant of Article 2 of the Protocol. It is this resort to war, contrary to the terms of the Protocol, which is the chief breach of the Protocol against which its chief Sanctions are ordered. By Article 10 of the Protocol[2] every State which resorts to war in violation of the undertakings either in the Covenant or in the Protocol, is an aggressor. It will be necessary to consider only the provisions of the Protocol forbidding a resort to war, for it would be impossible to have a resort to war contrary to the Covenant which would not also be a resort to war contrary to the Protocol. The provisions of the Protocol go farther than those of the Covenant in this regard. It is true that there are in the Covenant certain engagements by Members of the League not to resort to war. These are found in Articles 12, 13 and 15; but it is unnecessary to consider them in detail, for any resort to war contrary to the provisions of those Articles of the Covenant would clearly also be contrary to the general engagements of Article 2 of the Protocol. The Report to the Assembly[3] seems to infer that a violation of the obligation of Article 10 of the Covenant on the part of all Members of the League to respect the territorial integrity and political independence of other Members might be a resort to war not included in the language of the Protocol; but I think that {55} any such forcible violation would be within the terms of the Protocol also. It is against the aggressor that the Sanctions of the Protocol are set up and accordingly the provisions of the Protocol defining an aggressor and the procedure for determining what State is an aggressor are of the utmost consequence. The definitions of an aggressor under the Protocol are complex in their language though not in their fundamental idea, which is that aggression is a resort to war instead of to arbitration.[4] The language of the definitions is obscured by certain presumptions (Article 10) and by the procedure laid down for the determination of an aggressor. The general definition of an aggressor in the first paragraph of Article 10 of the Protocol I have mentioned above. It is well, however, to quote it in full: "Every State which resorts to war in violation of the undertakings contained in the Covenant or in the present Protocol is an aggressor. Violation of the rules laid down for a demilitarized zone shall be held equivalent to resort to war."