State immunity — Jurisdictional immunity — Commercial activity exception — Nature of acts giving rise to cause of action — Mexican bank refusing to honour terms of certificates of deposit because of Mexican exchange regulations — Whether a commercial act — Whether bank acting as instrumentality of Mexican State — Distinction between bank’s acts and act of Mexican Government in promulgating regulations

Relationship of international law and municipal law — Act of State and justiciability — Nature of United States act of State doctrine — Judicial restraint in matters of foreign relations — Whether there is a commercial activity exception to the act of State doctrine — Enactment of exchange control regulations — Whether a sovereign or commercial activity — Treaty exception to act of State doctrine

Jurisdiction — Territorial — Property — Situs of debt — Application of exchange control regulations — State with which debt most closely connected

Economics, trade and finance — International Monetary Fund — National exchange control regulations — Allegation that regulations contrary to IMF Articles of Agreement — Approval of regulations by IMF — Effect of approval on municipal court

Comity — Nature of — Act of State doctrine and sovereign immunity as application of principles of comity — The law of the United States