European Union law is the only judicial system in addition to the national jurisdictions of member states. The laws of the European Union override the rules of the Member States in many areas, especially in the European common market. The legislation enacted by the European Union through agreements directly impacts the internal rules of all member states and is binding for all countries. It is necessary to unconditionally accept the union laws in order to join the European Union.

The legal system of the European Union consists of a number of legal procedures, including regulations laid down in the Community bylaws, Directives and Decisions. The treaties of the Union constitute the basis for all legislative acts and procedures and set out various ways to legislate in different areas. An important feature of the legislative procedure of the European Union is that the legislation may always be proposed by the European Commission rather than by one of the member states or parliamentarians. Two other important elements are the common decision mechanism that gives the European Parliament the right to veto a draft law and the possibility of the parliament to make suggestions and level criticisms that are not binding on the union leaders. In many cases, legislative drafts need to be approved at the Summit.