State immunity — Jurisdictional immunity — Contracts of employment and commercial concessions — United States air force base in the Philippines — Disputes concerning employment of cook at restaurant and concession for barbers’ shops — Claims against United States — Whether United States entitled to jurisdictional immunity — Restrictive doctrine of State immunity — Whether contracts relating to exercise of commercial functions — Whether entry into contracts by United States Government constituting waiver of immunity — Philippines-United States Military Bases Agreement, 1947

State immunity — Jurisdictional immunity — United States armed forces — United States agents abroad acting in the performance of official duties — Undercover surveillance of drug offences — Claim for damages by alleged offender against agents — Whether United States entitled to invoke jurisdictional immunity as bar to claim

Relationship of international law and municipal law — Rules of customary international law — Incorporation into municipal legal order — Philippine Constitution, Article II(2) — The law of the Philippines