Conception and character of Intervention.
§ 134. Intervention is dictatorial interference by a State in the affairs of another State for the purpose of maintaining or altering the actual condition of things. Such intervention can take place by right or without a right, but it always concerns the external independence or the territorial or personal supremacy of the respective State, and the whole matter is therefore of great importance for the position of the States within the Family of Nations. That intervention is, as a rule, forbidden by the Law of Nations which protects the International Personality of the States, there is no doubt. On the other hand, there is just as little doubt[211] that this rule has exceptions, for there are interventions which take place by right, and there are others which, although they do not take place by right, are nevertheless admitted by the Law of Nations and are excused in spite of the violation of the Personality of the respective States they involve.
[211] The so-called doctrine of non-intervention as defended by some Italian writers (see Fiore, I. No. 565), who deny that intervention is ever justifiable, is a political doctrine without any legal basis whatever.
Intervention can take place in the external as well as in the internal affairs of a State. It concerns in the first case the external independence, and in the second either the territorial or the personal supremacy. But it must be emphasised that intervention proper is always dictatorial interference, not interference pure and simple.[212] Therefore intervention must neither be confounded with good offices, nor with mediation, nor with intercession, nor with co-operation, because none of these imply a dictatorial interference. Good offices is the name for such acts of friendly Powers interfering in a conflict between two other States as tend to call negotiations into existence for the peaceable settlement of the conflict, and mediation is the name for the direct conduct on the part of a friendly Power of such negotiations.[213] Intercession is the name for the interference consisting in friendly advice given or friendly offers made with regard to the domestic affairs of another State. And, lastly, co-operation is the appellation of such interference as consists in help and assistance lent by one State to another at the latter's request for the purpose of suppressing an internal revolution. Thus, for example, Russia sent troops in 1849, at the request of Austria, into Hungary to assist Austria in suppressing the Hungarian revolt.
[212] Many writers constantly commit this confusion.
[213] See below, [vol. II. § 9].
Intervention by Right.
§ 135. It is apparent that such interventions as take place by right must be distinguished from others. Wherever there is no right of intervention, although it may be admissible and excused, an intervention violates either the external independence or the territorial or the personal supremacy. But if an intervention takes place by right, it never contains such a violation, because the right of intervention is always based on a legal restriction upon the independence or territorial or personal supremacy of the State concerned, and because the latter is in duty bound to submit to the intervention. Now a State may have a right of intervention against another State, mainly for six reasons:[214]
[214] The enumeration is not intended to be exhaustive.
(1) A Suzerain State has a right to intervene in many affairs of the Vassal, and a State which holds a protectorate has a right to intervene in all the external affairs of the protected State.