§ 28. The above-described characteristics of compulsive means for the settlement of international differences make it necessary to mention the distinction between such means and an ultimatum. The latter is the technical term for a written communication by one State to another which ends amicable negotiations respecting a difference, and formulates, for the last time and categorically, the demands to be fulfilled if other measures are to be averted. An ultimatum is, theoretically at least, not a compulsion, although it can practically exercise the function of a compulsion, and although compulsive means, or even war, can be threatened through the same communication in the event of a refusal to comply with the demand made.[29] And the same is valid with regard to withdrawal of diplomatic agents, to military and naval demonstrations, and the like, which some publicists[30] enumerate among the compulsive means of settlement of international differences. Although these steps may contrive, indirectly, the settlement of differences, yet they do not contain in themselves any compulsion.
[29] See Pradier-Fodéré, VI. No. 2649, and below, § [95].
[30] See Taylor, §§ 431, 433, 441; Moore, VII. §§ 1089, 1091, 1099; Pradier-Fodéré, VI. No. 2633.
II RETORSION
Vattel, II. § 341—Hall, § 120—Westlake, II. p. 6—Phillimore, III. § 7—Twiss II. § 10—Taylor, § 435—Wharton, III. § 318—Moore, VII. § 1090—Wheaton, § 290—Bluntschli, § 505—Heffter, § 110—Bulmerincq in Holtzendorff, IV. pp. 59-71—Ullmann, § 159—Bonfils, Nos. 972-974—Despagnet, Nos. 484-486—Pradier-Fodéré, VI. Nos. 2634-2636—Rivier, II. § 60—Calvo, III. § 1807—Fiore, II. Nos. 1226-1227, and Code, Nos. 1386-1390—Martens, II § 105.
Conception and Character of Retorsion.
§ 29. Retorsion is the technical term for the retaliation of discourteous or unkind or unfair and inequitable acts by acts of the same or a similar kind. Retorsion has nothing to do with international delinquencies, as it is not a means of compulsion in the case of legal differences, but only in the case of certain political differences. The act which calls for retaliation is not an illegal act; on the contrary, it is an act that is within the competence of the doer.[31] But a State can commit many legislative, administrative, or judicial acts which, although they are not internationally illegal, contain a discourtesy or unfriendliness to another State or are unfair and inequitable. If the State against which such acts are directed considers itself wronged thereby, a political difference is created which might be settled by retorsion.
[31] For this reason—see Heilborn, System, p. 352, and Wagner, Zur Lehre von den Streiterledigungsmitteln des Völkerrechts (1900), pp. 53-60—it is correctly maintained that retorsion, in contradistinction to reprisals, is not of legal, but only of political importance. Nevertheless, a system of the Law of Nations must not omit the matter of retorsion altogether, because retorsion is in practice an important means of settling political differences.
Retorsion, when justified.
§ 30. The question when retorsion is and when it is not justified is not one of law, and is difficult to answer. The difficulty arises from the fact that retorsion is a means of settling such differences as are created, not by internationally illegal, but by discourteous or unfriendly or unfair and inequitable acts of one State against another, and that naturally the conceptions of discourtesy, unfriendliness, and unfairness cannot be defined very precisely. It depends, therefore, largely upon the circumstances and conditions of the special cases whether a State will or will not consider itself justified in making use of retorsion. In practice States have frequently made use of retorsion in cases of unfair treatment of their citizens abroad through rigorous passport regulations, exclusion of foreigners from certain professions, the levy of exorbitant protectionist or fiscal duties; further, in cases of refusal of the usual mutual judicial assistance, refusal of admittance of foreign ships to harbours, and in similar cases.