The European Union is unique among international organizations in having a complex and highly developed system of internal law which has direct effect within the legal systems of its member states. Unlike other bodies of international law, it is generally recognized that European Union law overrides the national laws of its member states.
There are three sources of Union law:
- primary legislation: the treaties
- secondary legislation: regulations, directives, decisions, recommendations and opinions made by the Union's institutions in accordance with the treaties
- decisions of the European Court of Justice and the Court of First Instance
The primary legislation, or treaties, are effectively the constitutional law of the European Union. They lay down the basic policies of the Union, establish its institutional structure, legislative procedures, and the powers of the Union. The treaties that make up the primary legislation include:
- the ECSC Treaty of 1951
- the EEC Treaty of 1957
- the EURATOM Treaty of 1957
- the Merger Treaty of 1965
- the Acts of Accession of the United Kingdom, Ireland and Denmark (1972)
- the Budgetary Treaty of 1970
- the Budgetary Treaty of 1975
- the Act of Accession of Greece (1979)
- the Acts of Accession of Spain and Portugal (1985)
- the Single European Act of 1986
- the Treaty of Maastricht of 1992
- the Acts of Accession of Austria, Sweden and Finland (1994)
- the Treaty of Amsterdam of 1997
- the Treaty of Nice of 2001
Secondary legislation also includes interinstitutional agreements, which are agreements made between European Union institutions clarifying their respective powers, especially in budgetary matters. The Parliament, Commission and Council are capable of entering into such agreements.
The classification of legislative acts varies among the First, Second and Third Pillars.
In the case of the first pillar: Secondary legislation is classified based on to whom it is directed, and how it is to be implemented. Regulations and directives bind everyone, while decisions only affect the parties to whom they are addressed (which can be individuals, corporations, or member states). Regulations have direct effect, i.e. they are binding in and of themselves as part of national law, while directives require implementation by national legislation to be effective. However, states that fail or refuse to implement directives as part of national law can be fined by the European Court of Justice.
Specific topics in EC law