International law in general — Relation to municipal law — Treaties and international agreements — Universal Postal Convention — Effect of absence of approval by Congress or ratification by Senate — The law of the United States

Treaties — Conclusion and operation — Necessity for assent of State to be party — Universal Postal Convention — The law of the United States

Treaties — Conclusion and operation — Effect in municipal law — Universal Postal Convention — Neither law nor treaty in absence of passage through Congress or ratification by Senate — The law of the United States

Jurisdiction — In general — Personal — Over nationals abroad — Foreign mail — Whether Fifth Amendment applicable to foreign mail between United States citizens — Universal Postal Convention — The law of the United States