--- by contract and agreement....International Law is the Supreme Law of the Land in every country on this planet???
---- Pan-American conferences--- TITLE: Pan-American conferences (1826-1948) ...states of the Western Hemisphere (Canada usually excluded). Between 1826 and 1889, several meetings between American states were held to discuss problems of common defense and juridical matters. The First International Conference of American States (1889–90), which was held largely as the result of the efforts of U.S. Secretary of State James G. Blaine, established the International Union...http://www.cfr.org/sovereignty/montevideo-convention-rights-duties-states/p15897