that two element rule of customary international law.3 From the poor drafting of the International Court of Justice (ICJ) Statute, we could understand customary international law to be constituted and evidenced on a different basis,4 but there does not appear to be much support for considering state practice and opinio juris as factors or alternatives, or any legal rule other than elements.5 Applying the elements, authorities test whether they exist by sampling the practice of views of states, and through inductive and deductive reasoning, conclude whether the norm has been established or not.6 However, the Permanent Court of International Justice and ICJ have both asserted that some rules of customary international law can be sustained without rigid application of the two-element rule. In the Gulf of Maine case, the Court held that “a limited set of norms for ensuring the coexistence and vital cooperation of the members of the international community” exist without the rigorous need to establish state practice and opinio juris.7 The Court has reaffirmed its view on several occasions. In Armed Activities on the Territory of the Congo, the Court discovered customary international humanitarian law by examining the application of the Hague Convention Respecting the Laws and Customs of Land Warfare and customary international law on permanent sovereignty over natural resources by considering UN General Assembly (UNGA) Resolutions.8 In the Burkina Faso v Mali Frontier Dispute, the Court held that uti possidetis was customary international law because “it is logically connected with the phenomenon of the obtaining of independence”.9 In the Nicaragua case, the Court found that Common Article 3 of the Geneva Conventions was customary international law because it was in alignment with “elementary considerations of humanity”,10 the same reason that underpinned the Court’s judgment in the Corfu Channel case.11 Why the Court reaches these conclusions, and their meaning is not readily apparent. It might be that the Court is submitting that there are two forms of customary international law: one proved by state practice and opinio juris, and the other proved by “coexistence and vital cooperation”. Another view could be that there is only one type of customary international law, but it can be proved through two alternative means. Yet another view could be that where there is coexistence and vital cooperation, the burden of proving state practice and opinio juris is reduced. In short, there is a presumption in favor of a rule that is logically necessary for coexistence and vital cooperation. Yet, the ILC and the vast majority of authorities consistently affirm the two-element rule.12 The only way to understand maintaining the two-element rule and the reasoning of the ICJ, is to conclude that there is only one form of customary international law and it is proved by the two-element rule, but the actual proof of the elements can be presumed in cases where the rule pertains to coexistence and vital cooperation, elementary considerations of humanity, or otherwise logically deduced from the underlying phenomenon, or is articulated in common treaty practice or UNGA resolutions. It is unlikely that this lacking in the consistency and certainty required to constitute “constant and uniform usage”); IAN BROWNLIE, PRINCIPLES OF PUBLIC INTERNATIONAL LAW 4-11 (5th ed. 1998). 3 See Int’l L. Comm’n 4 Statute of the I.C.J., art. 38 (1)(b) (describing “international custom, as evidence of a general practice accepted as law” literally stating that custom is evidence of practice and opinio juris, the opposite of contemporary method); European Union Guidelines on Promoting Compliance with International Humanitarian Law (IHL), [2005] O.J. C327/04, para. 7 (Dec. 23, 2005) (“Customary international law is formed by the practice of States which they accept as binding upon them.”) 5 See Int’l L. Comm’n 6 See Delimit. of the Marit. Bdary in the Gulf of Maine Area (Can. v. U.S.) (Gulf of Maine case), Judgment, 1984 ICJ Reps. 246, para. 111 (Jan. 20); Cont. Shelf (Libya v. Malta), Judgment, 1985 ICJ Reps. 13, para. 27 (June 3); William Thomas Worster, The Inductive and Deductive Methods in Customary International Law Analysis: Traditional and Modern Approaches, 45 GEORGETOWN J. INT’L L. 445 (2014). 7 See Delimitation of the Maritime Boundary in the Gulf of Maine Area (Can. v. U.S.), Judgment, 1984 ICJ Reps. 246, para. 111 (Jan. 20); B. Simma & P. Alston, The Sources of Human Rights Law: Custom, Jus Cogens, and General Principles, in 12 AUST’LIAN YB INT’L L. 109 (1988-9) 8 See Armed Activities on the Territory of the Congo (D.R. Congo v. Uganda), Judgment, 2005 ICJ Reps. 168, paras. 16162, 213-14, 244 (Dec. 19) 9 See Frontier Dispute (Burkina Faso v. Mali), Judgment 1986 ICJ Reps. 554, para. 20 (Dec. 22). 10 See Military and Paramilitary Activities in and Against Nicaragua (Nicar. v U.S.), Judgment, 1986 ICJ Reps. 14, paras. 215, 218 (June 27) 11 See Corfu Channel (U.K. v Alb.), Judgment, 1949 ICJ Reps. 4, para. 219 (Apr. 9). 12 2 Electroniccopy copyavailable available at: at: https://ssrn.com/abstract=3091912 Electronic https://ssrn.com/abstract=3091912