International law Study Guide

📖 Core Concepts International Law – Rules, norms, customs, and standards that states and other actors feel bound to obey in their relations. Actors – States, international organisations, and non‑state groups that can create lawful or unlawful obligations. Rules vs. Norms – Rules: formal, usually written requirements. Norms: informal, customary guidelines shaped by practice. Consent & Enforcement – International law relies on sovereign consent; there is no universal enforcing authority. Treaty Law – Written agreements between states/organisations; binding under pacta sunt servanda (keep promises in good faith). Customary International Law – Requires state practice and opinio juris (belief that the practice is legally required). Peremptory Norms (jus cogens) – Hierarchical norms from which no derogation is permitted (e.g., prohibition of genocide, use of force). Monism vs. Dualism – Monism: international and domestic law form a single order (treaties can have direct effect). Dualism: separate orders; treaty must be incorporated by legislation. Jurisdiction Principles – Territorial, nationality (active personality), passive personality, protective, universal. UN Security Council – Primary responsibility for international peace and security; can authorize force, sanctions, or refer matters to regional organisations. Jus ad Bellum – Law governing the initiation of armed conflict (prohibition of force, self‑defence, UN‑authorized action). Jus in Bello – Law governing conduct in armed conflict (principles of distinction, proportionality, humanity). --- 📌 Must Remember Treaty Binding Rule: pacta sunt servanda – parties must perform treaties in good faith. Customary Law Elements: (1) Consistent State Practice, (2) opinio juris. Peremptory Norms: No derogation; examples – prohibition of genocide, slavery, torture, use of force. Erga Omnes Obligations: Duties owed to the international community as a whole (e.g., genocide prohibition). Monist Hierarchy: International treaty > conflicting national statute. Dualist Requirement: Treaty becomes domestic law only after legislative enactment. UNSC Authorization: Requires ≥9 votes and no veto from any of the five permanent members. Self‑Defence: Article 51 UN Charter – individual or collective self‑defence after an armed attack. Jus in Bello Principles: Distinction: Combatants vs. civilians. Proportionality: No excessive civilian harm relative to military advantage. ICJ Jurisdiction: Only states that are parties to the Statute; advisory opinions are authoritative but non‑binding. Complementarity (ICC) – Court steps in only when national courts are unwilling or unable to prosecute. --- 🔄 Key Processes Treaty Formation Negotiation → Signature → Ratification/Accession/Approval → Entry into force (per treaty terms). Treaty Interpretation (Vienna Convention Art. 31‑33) Textual meaning → Intent of parties (subjective) → Object & purpose (teleological). Customary Law Development Widespread, consistent state practice → Accompanied by opinio juris → Custom becomes binding. Creating Peremptory Norms General acceptance + no‑derogation clause in multiple treaties & customary practice → Elevated to jus cogens. ICJ Case Process State submits application → Written pleadings → Oral arguments → Judgment (binding on parties). UNSC Enforcement Action Draft resolution → Vote (≥9, no veto) → Adopted resolution → Implementation (sanctions, peacekeeping, force). --- 🔍 Key Comparisons Treaty Law vs. Customary Law Treaty: Written, consent‑based, can be modified by reservations. Customary: Unwritten, arises from practice + opinio juris, binds all (unless persistent objector). Monism vs. Dualism Monism: International law automatically part of domestic law; higher than conflicting statutes. Dualism: International law must be transformed by legislation before domestic effect. Territorial Jurisdiction vs. Universal Jurisdiction Territorial: Authority over events on a state's own territory. Universal: Authority over certain crimes (e.g., piracy, genocide) regardless of where they occur. --- ⚠️ Common Misunderstandings “International law has no enforcement” – It does have enforcement mechanisms (e.g., sanctions, diplomatic pressure, UN‑authorized force). “Only states are bound by customary law” – While customary law primarily binds states, erga omnes obligations apply to all actors. “All treaties are self‑executing” – Some treaties require domestic legislation to be enforceable (dualist systems). “UNSC can act without permanent‑member consent” – A veto by any P5 member blocks a binding resolution. “Jus ad Bellum and Jus in Bello are the same” – Jus ad Bellum governs why war may be started; Jus in Bello governs how war is fought. --- 🧠 Mental Models / Intuition “Layered Pyramid” – At the base are customary practice; above it, treaties; at the top, peremptory norms (overriding everything). “Consent Switch” – International law operates when the consent switch is ON for a state; peremptory norms keep the switch on even if a state tries to turn it off. “Jurisdiction Compass” – Point to the closest principle: territorial → nationality → protective → universal. --- 🚩 Exceptions & Edge Cases Persistent Objector – A state consistently objecting to a developing custom can avoid being bound. Reservations – States may enter reservations that modify treaty obligations, provided they do not defeat the treaty’s object and purpose. Ultra Vires Treaty – A treaty can be invalid if parties lack authority (e.g., signed by a non‑competent official). Flag State Jurisdiction – On the high seas, only the flag state has jurisdiction except for piracy (universal jurisdiction). --- 📍 When to Use Which Interpret a Treaty → Apply Vienna Convention hierarchy: text → intent → object/purpose. Determine Applicable Law in Private International Law → Identify lex causae (foreign law) vs. lex fori (forum law); use choice‑of‑law rules (lex domicilii, lex patriae). Assess State Responsibility → Use customary law for universal duties; refer to treaty provisions when parties are bound by a specific treaty. Choose Jurisdiction Basis → Start with territorial principle; if unavailable, consider nationality, protective, or universal jurisdiction. --- 👀 Patterns to Recognize “Treaty + Reservation = Modified Obligation” – Whenever a treaty is cited, check for any reservations or declarations. “Customary Law = Practice + Belief” – If a state practice is cited without opinio juris, it is not yet customary law. “UNSC Resolution Language” – Phrases like “under Chapter VII” signal binding force; “under Chapter VI” indicate non‑binding recommendations. “Peremptory Norm Invocation” – Look for language “no derogation” or “erga omnes” to identify jus cogens issues. --- 🗂️ Exam Traps Mistaking a Treaty for Customary Law – Remember treaties need consent; customs bind all (unless objected). Assuming All International Courts Have Binding Authority – Only ICJ judgments are binding on parties; advisory opinions are not. Confusing “Self‑Defence” with “Humanitarian Intervention” – Self‑defence requires an armed attack; humanitarian intervention lacks a clear UN‑authorised exception. Over‑extending Universal Jurisdiction – It applies only to specific crimes (piracy, genocide, war crimes, crimes against humanity). Neglecting the Persistent Objector Rule – A state that consistently objects during the formation of a custom is not bound. ---