Statute of the ICJ, Article 38(1) The Court…shall apply: a. international conventions, whether general or particular, establishing rules expressly recognized by the contesting states; b. international custom, as evidence of a general practice accepted as law; c. the general principles of law recognized by civilized nations; d. subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.

 Objective element  Subjective element --“opinio juris” [and no persistent objection]

 All states considered bound by a jus cogens or peremptory norm –e.g., “no slavery”  International norm preventing discrimination on basis of sex in transmitting citizenship to children  US persistently objecting to 18 as minimum age for soldiers

 Uniquely among sources of law, CIL is found in facts, i.e., ◦ evidence of how states behave (“state practice”) and ◦ evidence of why they behave that way (“opinio juris”)

 treaties  decisions of national and international courts  national legislation  opinions of national legal advisors  diplomatic correspondence  practice of international organizations  and more…

 Sources of State Practice in International Law (Ralph Gaebler & Maria Smolka-Day, eds.)

 Treaties may codify existing CIL  Emerging principles of CIL may begin to appear in treaties ◦ e.g., “right to intervene” art. 4(h) AU Constitutive Act  Treaty provisions used as evidence to show existence of CIL

 Dictionaries—esp. Parry and Grant Encyclopaedic Dictionary of International Law  Encyclopedias—esp. Max Planck Encyclopaedia of Public International Law (MPEPIL)  Specialized int’l law dictionaries and encyclopedias

 Watch for synonyms and related concepts  Emerging CIL principles prone to changes in terminology ◦ R2P—humanitarian intervention, and briefly, Annan Doctrine

 Restatement of the Law, Third, Foreign Relations Law of the United States ◦ not good on cutting-edge topics ◦ but new CIL principles relate to old—e.g., territorial sovereignty  Restatement =“writing of publicists”

 Prefer “learned societies”—best example for US = Restatement  Multi-edition int’l law treatises good too ◦ (Shaw, Oppenheim, Akehurst…)

 MPEPIL has bibliographies  LCSH headings ◦ some correspond to CIL concepts:  R2P under humanitarian intervention ◦ some are close: diplomatic immunity = LCSH Diplomatic Privileges and Immunities

 Full-text law review databases  [your CIL concept] /s CIL OR “international custom” OR “customary international law”  Consider modifying to reflect specialized part of IL ◦ e.g., “customary international humanitarian”

 legal periodical indexes  Peace Palace Library catalogue—books and articles  news sources for current state behavior

 (Start with cases mentioned in sources above, right?)  Useful sources ◦ International Law Reports ◦ Oxford Reports on International Law ◦ World Court Digest

 Multinational—UN, TIARA  National —e.g., Australian  Specialized—e.g., humanitarian law—ICRC database  Look for relevant provisions ◦ multilateral—count the parties ◦ bilateral—count total number of treaties/total number of different parties

 digests — Digests of United States Practice in International Law  yearbooks ◦ national ◦ topical—Yearbook of International Humanitarian Law

 Practice of intergovernmental organizations ◦ Smaller states often can only express views this way —e.g., by voting on UN res ◦ Example: UN resolutions on use of force, used by ICJ in Nicaragua case to show norm of CIL.  Focus on UN, then regional  UNBisnet; UN Yearbook  Recent topics—may be Googleable

 national laws  topical collections of legislation ◦ e.g., for CIL on terrorism, UN’s database of national laws on terrorism  court opinions

 To find them ◦ subject research guides (e.g., at GlobaLex) ◦ texts on int’l/foreign legal research ◦ web searches

 Identify examples of international situations where CIL principle might have arisen ◦ e.g. for R2P—Rwanda, Libya, Syria, Côte d’Ivoire ◦ e.g. for use of unmanned drones—Pakistan  Use keywords from these situations as search terms in news databases, on web, etc.

 Gap-filling  Drawn from national legal systems  Mostly procedural, jurisdictional, administrative, but also fairness  Bin Cheng, General Principles of Law (1953)

 state responsibility for acts of agents  estoppel  waiver  reparations

 4RmI 4RmI