Relationship of international law and municipal law — Act of State and justiciability — Nature of act of State doctrine in United States law — Respect for sovereign independence of State — Judicial restraint in matters of foreign relations — Whether act of State doctrine applicable to acts committed in violation of international law — Murder — Whether doctrine applicable to unauthorized acts of State official — Whether doctrine applicable to sovereign acts occurring within the United States — Whether judicial proceedings in foreign State constituting act of State — Relationship between act of State doctrine and doctrine of sovereign immunity

State immunity — Jurisdictional immunity — Exception to immunity — Non-sovereign acts — Assassination of United States resident in the United States — Assassination arranged by foreign government official — Whether falling within noncommercial tort exception — Requirement that tort committed within “scope of employment” — Doctrine of respondeat superior — Application of doctrine in determining whether assassination carried out within “scope of employment” — Whether foreign State entitled to immunity under discretionary function exception — Foreign Sovereign Immunities Act 1976 — Whether superseding act of State doctrine — The law of the United States