War a contention.
§ 55. In any case, it is universally recognised that war is a contention, which means, a violent struggle through the application of armed force. For a war to be in existence, two or more States must actually have their armed forces fighting against each other, although the commencement of a war may date back to its declaration or some other unilateral initiative act. Unilateral acts of force performed by one State against another without a previous declaration of war may be a cause of the outbreak of war, but are not war in themselves, as long as they are not answered by similar hostile acts by the other side, or at least by a declaration of the other side that it considers the particular acts as acts of war. Thus it comes about that acts of force performed by one State against another by way of reprisal or during a pacific blockade in the case of an intervention are not necessarily initiative acts of war. And even acts of force illegally performed by one State against another, such, for instance, as occupation of a part of its territory, are not acts of war so long as they are not met with acts of force from the other side, or at least with a declaration from the latter that it considers the particular acts as acts of war. Thus, when Louis XIV. of France, after the Peace of Nimeguen, instituted the so-called Chambers of Reunion and in 1680 and 1681 seized the territory of the then Free Town of Strassburg and other parts of the German Empire without the latter's offering armed resistance, these acts of force, although doubtless illegal, were not acts of war.
War a contention between States.
§ 56. To be considered war, the contention must be going on between States. In the Middle Ages wars were known between private individuals, so-called private wars, and wars between corporations, as the Hansa for instance, and between States. But such wars have totally disappeared in modern times. It may, of course, happen that a contention arises between the armed forces of a State and a body of armed individuals, but such contention[59] is not war. Thus the contention between the Raiders under Dr. Jameson and the former South African Republic in January 1896 was not war. Nor is a contention with insurgents or with pirates a war. And a so-called civil war[60] need not be from the beginning nor become at all a war in the technical sense of the term according to International Law. On the other hand, to an armed contention between a suzerain and its vassal[61] State the character of war ought not to be denied, for both parties are States, although the fact that the vassal makes war against the suzerain may, from the standpoint of Constitutional Law, be considered rebellion. And likewise an armed contention between a full Sovereign State and a State under the suzerainty of another State, as, for instance, the contention between Servia and Bulgaria[62] in 1885, is war. Again, an armed contention between one or more member-States of a Federal State and the latter ought to be considered as war in the technical sense of the term, according to International Law, although, according to the constitution of Federal States, war between the member-States as well as between any member-State and the Federal State itself is illegal, and recourse to arms by a member-State may therefore correctly, from the standpoint of the constitution, be called rebellion. Thus the War of Secession within the United States between the Northern and the Southern member-States in 1861-1865 was real war.
[59] Some publicists maintain, however, that a contention between a State and the armed forces of a party fighting for public rights must be considered as war. See, for instance, Bluntschli, § 113, and Fiore, III. § 1265.
[62] Bulgaria was at that time still a vassal State under Turkish suzerainty.
War a contention between States through armed forces.
§ 57. It must be emphasised that war nowadays is a contention of States through their armed forces. Those private subjects of the belligerents who do not directly or indirectly belong to the armed forces do not take part in the armed contention: they do not attack and defend, and no attack is therefore made upon them. This fact is the result of an evolution of practices totally different from those in vogue in former times. During antiquity and the greater part of the Middle Ages war was a contention between the whole of the populations of the belligerent States. In time of war every subject of one belligerent, whether an armed and fighting individual or not, whether man or woman, adult or infant, could be killed or enslaved by the other belligerent at will. But gradually a milder and more discriminative practice grew up, and nowadays the life and liberty of such private subjects of belligerents as do not directly or indirectly belong to their armed forces are safe, as is also, with certain exceptions, their private property.