The principle of the supremacy of EU law means that EU law takes precedence over the national law of EU member states. This principle was established by the European Court of Justice in its 1964 ruling in the Costa v ENEL case.
The principle of supremacy is based on the idea that the EU is a union of member states, and that the EU legal order is separate and superior to the national legal orders of its member states. This means that if there is a conflict between EU law and national law, EU law takes precedence and must be applied by the national courts.
The supremacy of EU law ensures the uniform application and interpretation of EU law across all member states, and prevents member states from adopting laws that conflict with EU law. It also means that national courts are required to set aside any national laws that conflict with EU law.
However, the principle of supremacy does not mean that the EU can override the fundamental principles of national legal systems or the constitutional principles of member states. The EU is required to respect the fundamental rights of individuals and the sovereignty of its member states.
You can learn more about this topic and relevant case law with our EU Law notes.
