Monism and Dualism in International Law - Examples

Examples

In some countries, such as the UK for instance, the dualist view is predominant. International law is only part of British national law once it is accepted in national law. A treaty

"has no effect in municipal law until an Act of Parliament is passed to give effect to it. In other countries this distinction tends to be blurred. In the vast majority of democratic countries outside the Commonwealth, the legislature, or part of the legislature, participates in the process of ratification, so that ratification becomes a legislative act, and the treaty becomes effective in international law and in municipal law simultaneously. For instance, the Constitution of the United States provides that the President 'shall have power, by and with the advice and consent of the Senate, to make treaties, provided two-thirds of the Senators present concur'. Treaties ratified in accordance with the Constitution automatically become part of the municipal law of the USA".

The United States of America has a "mixed" monist-dualist system; international law applies directly in US courts in some instances but not others. US Constitution, art. VI, does indeed say that treaties are part of the Supreme Law of the Land, as suggested by the quote above; however, its Supreme Court, as late as the recent case of Medellín v. Texas, has restated that some treaties are not "self-executing." Such treaties must be implemented by statute before their provisions may be given effect by national and sub-national courts. Similarly with regard to customary international law, its Supreme Court stated, in the case of the Pacquete Habana (1900), that "international law is part of our law." However, it also said that international law would not be applied if there is a controlling legislative, executive, or judicial act to the contrary...