State immunity — Jurisdictional immunity — Commercial activity exception — State corporation — Requirement of sufficient nexus between case and the United States — Whether sufficient that the corporation doing business in the United States — Requirement of direct effect in the United States — Requirement that effect be substantial and foreseeable — State corporation unaware that aircraft engine it was servicing in Ireland was to be used in the United States — Whether financial hardship suffered in the United States due to destruction of engine constituting a direct effect — United States Foreign Sovereign Immunities Act 1976 — The law of the United States