National law is the set of laws that governs the relationship between a country and its citizens. It can be divided into two types: federal law, which includes legislation passed by Congress and signed by the president; and state law, which is a set of rules that applies to the states.
Various international organizations have been created, and treaties have been made, that regulate the international legal order. Among the most important of these is the United Nations, founded in 1945.
There are also a number of international conventions, including those on human rights, and others on trade. These have been ratified by a number of countries, and become part of their national law.
The primacy of EU law is a legal principle that gives EU law precedence over conflicting national law within an EU member state (see Article 127, EU Code of Conduct). This may lead to the disapplying of national case-law that represents an obstacle to the full application of EU law and any provision of national law which is contrary to a provision of EU law with direct effect.
In the United States, ratified human rights treaties and customary international law are the “supreme law of the land,” and are generally binding on federal and state governments. Moreover, because of the Supremacy Clause of the Constitution, which makes all treaties made or which shall be made under the authority of the United States supreme law, U.S. ratified human rights treaties and customary law are the basis of United States federal constitutional law.