§ 50. Intervention as a means of settling international differences is only a special kind of intervention in general, which has already been discussed.[54] It consists in the dictatorial interference of a third State in a difference between two States for the purpose of settling the difference in the way demanded by the intervening State. This dictatorial interference takes place for the purpose of exercising a compulsion upon one or both of the parties in conflict, and must be distinguished from such attitude of a State as makes it a party to the very conflict. If two States are in conflict and a third State joins one of them out of friendship or from any other motive, such third State does not exercise an intervention as a means of settling international differences, but becomes a party to the conflict. If, for instance, an alliance exists between one of two States in conflict and a third, and if eventually, as war has broken out in consequence of the conflict, such third State comes to the help of its ally, no intervention in the technical sense of the term takes place. A State intervening in a dispute between two other States does not become a party to their dispute, but is the author of a new imbroglio, because such third State dictatorially requests those other States to settle their difference in a way to which both, or at any rate one of them, objects. An intervention, for instance, takes place when, although two States in conflict have made up their minds to fight it out in war, a third State dictatorially requests them to settle their dispute through arbitration.
[54] See above, [vol. I. §§ 134]-138.
Intervention, in the form of dictatorial interference, must, further, be distinguished from such efforts of a State as are directed to induce the States in conflict to settle their difference amicably by proffering its good offices or mediation, or by giving friendly advice. It is, therefore, incorrect when some jurists[55] speak of good offices and the like as an "amicable" in contradistinction to a "hostile" intervention.
[55] Thus, for instance, Rivier, II. § 58. See also above, [vol. I. § 134].
Mode of Intervention.
§ 51. Intervention in a difference between two States is exercised through a communication of the intervening State to one or both of the conflicting States with a dictatorial request for the settlement of the conflict in a certain way, for instance by arbitration or by the acceptance of certain terms. An intervention can take place either on the part of one State alone or of several States collectively. If the parties comply with the request of the intervening State or States, the intervention is terminated. If, however, one or both of the parties fail to comply with the request, the intervening State will either withdraw its intervention or proceed to the performance of acts more stringent than a mere request, such as pacific blockade, military occupation, and the like. Even war can be declared for the purpose of an intervention. Of special importance are the collective interventions exercised by several great Powers in the interest of the balance of power and of humanity.[56]
[56] See above, [vol. I. §§ 136] and [137].
Time of Intervention.
§ 52. An intervention in a difference between two States can take place at any time from the moment a conflict arises till the moment it is settled, and even immediately after the settlement. In many cases interventions have taken place before the outbreak of war between two States for the purpose of preventing war; in other cases third States have intervened during a war which had broken out in consequence of a conflict. Interventions have, further, taken place immediately after the peaceable settlement of a difference, or after the termination of war by a treaty of peace or by conquest, on the grounds that the conditions of the settlement or the treaty of peace were against the interests of the intervening State, or because the latter would not consent to the annexation of the conquered State by the victor.[57]
[57] With regard to the question of the right of intervention, the admissibility of intervention in default of a right, and to all other details concerning intervention, the reader must be referred above, [vol. I. §§ 135]-138.