Economics, trade and finance — Currency regulation — Imposition of currency controls a sovereign act — Debt — Situs of debt — Certificates of deposit payable in Mexico — Mexican legislation requiring that payment be made in pesos convertible only at official rate of exchange — Application of act of State doctrine

Expropriation — Of debt — Imposition of currency controls — Whether involving a taking of property — Situs of debt — Non-justiciability of taking by foreign sovereign within own territory — Act of State doctrine

Relationship of international law and municipal law — Act of State and justiciability — United States act of State doctrine — Whether subject to exception for commercial activities — Imposition of exchange controls — Whether a commercial activity — Territorial scope — Debts affected situated in Mexico — The law of the United States