International Law Research Checklist

Open the matter file and document the operative facts, the disputed legal question, and the client's desired outcome. Flag time-sensitive elements — provisional-measures requests, expiring force-majeure windows, upcoming treaty-body sessions — that compress the research timeline.

Conflict-of-laws questions (Rome I/II in EU matters; Hague Conference instruments globally) follow a different track than public-international questions arising under treaty or custom. Hybrid matters — investor-state disputes, transboundary environmental claims, sanctions enforcement — sit on both tracks and need both analyses.

List every party, their nationality, place of incorporation, and any treaty-based standing (BIT investor, refugee under the 1951 Convention, ICCPR individual communicant). Forum nexus determines which jurisdictional bases — territorial, nationality, passive personality, protective, universal — are even arguable.

For state-respondent matters, check declarations under ICJ Statute Article 36(2) and any compromissory clauses in relevant treaties. For private parties, check arbitral seats, BIT consent provisions, and forum-selection clauses. Document gaps where jurisdiction is contested or prima facie absent.

Apply Rome I (contractual) and Rome II (non-contractual) regulations for EU-touching matters; otherwise look to the Hague Principles on Choice of Law in International Commercial Contracts and the forum's domestic conflicts rules. Document mandatory rules and public-policy carve-outs that override party choice — these are the most-litigated escape hatches.

State-respondent claims trigger FSIA (US), the State Immunity Act 1978 (UK), or the 2004 UN Convention on Jurisdictional Immunities analysis. Service on diplomatic agents runs into VCDR 1961 / VCCR 1963 immunities. Assess commercial-activity and waiver exceptions before drafting any pleading.

International tribunals (ICJ, ICC, ITLOS, PCA, WTO DSB, ICSID, regional human-rights courts) have specific jurisdictional gateways. Domestic courts applying international law follow a separate procedural track. The answer here determines whether the procedural-posture section runs the international-filing branch.

Get authoritative texts from the UN Treaty Series (treaties.un.org). Verify ratification status, reservations, and declarations on each Depositary page — a treaty in force generally is not the same as in force between these parties. Cross-check regional databases (CoE, OAS, AU) for instruments not registered with the UN.

Identify state practice (legislation, diplomatic correspondence, military manuals, UNGA voting records) and opinio juris. Use the ILC's 2018 Draft Conclusions on Identification of Customary International Law as the analytical framework. ICRC's CIHL database is the starting point for IHL questions.

Compile UNGA resolutions, ILC draft articles with commentaries, ICJ advisory opinions, and authoritative restatements. Soft-law instruments do not bind on their own but inform treaty interpretation through VCLT Article 31(3)(c) and frequently feed into emerging custom.

Apply Article 31 first (ordinary meaning in context, object and purpose, subsequent practice and agreements) before resorting to Article 32 supplementary means (preparatory work, circumstances of conclusion). Both the WTO Appellate Body and the ICJ expect this sequencing — leading with travaux is a common briefing mistake.

Pull judgments from icj-cij.org; use ITLOS, PCA, ICSID, and WTO Appellate Body archives for specialized fora. For human-rights matters run HUDOC (ECtHR) or the IACHR jurisprudence database. Note dissents and separate opinions — they often signal where the law is moving and frame the next round of litigation.

Pull treatises and journal articles from Oxford Public International Law (OPIL), HeinOnline's Foreign & International Law Resources, and ASIL's Electronic Resource Guide. ICJ Statute Article 38(1)(d) treats qualified publicists as a subsidiary source — citation to recognized authorities (Crawford, Brownlie, Shaw) carries weight before international tribunals.

Calendar admissibility windows: ICJ time-limits set by order, ECtHR's four-month rule under Protocol 15, WTO panel-establishment deadlines, ICSID's three-year limitation in many BITs. Tickle each deadline with redundancy — primary attorney plus paralegal docket entry plus calendar reminder at 60/30/7 days out.

For ICJ: review Rules of Court Articles 38-43 on institution of proceedings. For ICC: Rome Statute Article 14 referrals or Article 15 proprio motu authorization. For ICSID: Schedule C and the Arbitration Rules. Each forum has unique pleading conventions, page limits, and exhibit-numbering rules — confirm format before drafting substance.

Catalog exhaustion of local remedies (the Interhandel rule), continuous nationality for diplomatic protection, jus standi, prior waiver, and time bars. The earlier these are flagged, the more strategy options remain open — late-discovery barriers often force dismissal or a switch of forum.

For arbitral awards: New York Convention 1958 (170+ contracting states) and ICSID Convention Article 54 (awards treated as final domestic judgments). For ICJ judgments: the UN Charter Article 94 mechanism. For human-rights judgments: domestic implementing legislation and Committee of Ministers supervision (ECtHR). Map enforcement before counseling the client on remedies — a paper victory with no enforcement path changes the litigation calculus.

Subscribe to the relevant tribunal RSS feeds, ASIL Insights, EJIL:Talk!, and OPIL's news service. For treaty-body output, subscribe to the OHCHR jurisprudence database. Monitoring catches the dispositive new authority that drops mid-research and prevents a stale memo from going to the client.

Issue the research memorandum to the responsible attorney with citations to primary sources (treaty articles, judgment paragraphs), the controlling publicist commentary, and a clear bottom-line conclusion with confidence level. Capture sign-off before any external use — this is the audit trail for malpractice and Rule 1.1 competence purposes.