Published online by Cambridge University Press: 20 April 2017
The Judgment of November 20,1950, of the International Court of Justice in the Colombian-Peruvian Asylum Case provides a noteworthy illustration of the judicial technique employed in making a determination as to the existence or non-existence of a rule of customary international law in a particular case.
1 I.C.J. Keports, 1950, p. 266; this Journal, Vol. 45 (1951), p. 179.
2 Manley O. Hudson, The Permanent Court of International Justice, 1920-1942— A Treatise (1943), p. 609. Cf. J. L. Brierly, The Law of Nations (4th ed., 1949), pp. 60 ff.; Hans Kelsen, The Law of the United Nations (1950), p. 533.
3 U. N. Doc. A/CN.4/16, March 3, 1950. This paragraph was omitted from the Eeport of the International Law Commission covering its Second Session, 1950, U. N. Doc. A/1316; this Journal, Supp., Vol. 44 (1950), p. 105.
4 See, for example, The Scotia (1871), 14 Wall. 170; The Paquete Habana (1900), 175 XJ. S. 677; The Lotus (1927), P.C.I.J., Ser. A, No. 10.
5 Max Sørensen, Les Sources du Droit International (1946), p. 85.
6 See Georg Schwarzenberger, International Law, Vol. I (2d ed., 1949), pp. 8 ff.
7 Cf. Helen Silving, “ ‘Customary Law’: Continuity in Municipal and International Law,” 31 Iowa Law Eeview (1946), pp. 614, 625.
8 P.C.I.J., 8er. A, No. 10, p. 28. See, generally, on custom, Lazare Kopelmanas, “Custom as a Means of the Creation of International Law,” British Year Book of International Law, 1937, pp. 127-151; Charles Rousseau, Principes Généraux du Droit International Public, Vol. I (1944), pp. 815-862; Sørensen, op. cit., pp. 84-111.
9 See Sørensen, op. cit., pp. 105 ff.; Silving, loc. cit., pp. 622 ff.; Paul Guggenheim, “Les deux éléments de la coutume en Droit international,” in La Technique et les Principes du Droit Public—Éudes en I’Honneur de Georges Scelle (1950), Vol. I, pp. 275 ff.
10 (1900), 175 U. S. 677.
11 Loc. cit., pp. 276-278. Cf. The Lotus Case, loc. cit., where, examining the practice of states in exercising criminal jurisdiction over foreigners and noting the absence of protests by states against the exercise of such jurisdiction, the Permanent Court of International Justice had little difficulty in concluding that the evidence failed to prove the existence of the opinio juris required forthe establishment of a customary rule of international law in the sense contended for by the French Government.