Consular relations — Consuls — Functions — Protection of nationals abroad — Right of Consul to represent nationals in courts of receiving State — Vienna Convention on Consular Relations, 1963, Article 5(1) — Representation subject to practices and procedures of receiving State — Mexico-United States Consular Convention, 1942, Article VI(2)(d)

Treaties — Interpretation — Application by municipal courts — Intention of the parties — Statements by United States Executive as evidence of parties' intentions — Whether conclusive

Relationship of international law and municipal law — Treaties — Interpretation — By municipal courts — Statements by United States Executive — Extent to which courts bound by Executive's interpretation of treaties — Customary international law — Consular protection of nationals abroad — The law of the United States