In other states, like in Germany, treaties have the same effect as legislation, and by the principle of Lex posterior derogat priori ("Later law removes the earlier"), only take precedence over national legislation enacted prior to their ratification.
[2] Dualists emphasize the difference between national and international law, and require the transposition of the latter into the former.
However, the international court does not permit the invocation of contrary domestic laws as a defence.
Again, from a human rights point of view, if a human rights treaty is accepted for purely political reasons, and states do not intend to fully translate it into national law or to take a monist view on international law, then the implementation of the treaty is very uncertain.
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" (Article II (2)).
Treaties ratified in accordance with the Constitution automatically become part of the municipal law of the United States.
[7]The United States has a "mixed" monist-dualist system; international law applies directly in US courts in some instances but not others.
The Constitution's Supremacy Clause states that treaties are part of the supreme law of the land, as suggested by the quote above; however, the U.S. Supreme Court, in Medellín v. Texas (2008),[8] held 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.
However, it also said that international law would not be applied if there is a controlling legislative, executive, or judicial act to the contrary.
[9] International law does not determine which point of view is to be preferred, monism or dualism.
Either they adopt a constitution that implements a monist system so that international law can be applied directly and without transformation, or they do not.
If a judge in a monist state makes mistakes when applying international law, then the country violates international law just as much as a dualist country that, for one reason or another, does not allow its judges to apply international law directly and fails to translate or fails to translate correctly and effectively.