Member state of the European Union

The European Union (EU) comprises 28 member states. Each member state is party to the founding treaties of the union and thereby subject to the privileges and obligations of membership. Unlike members of most international organisations, the member states of the EU are subjected to binding laws in exchange for representation within the common legislative and judicial institutions. Member states must agree unanimously for the EU to adopt policies concerning defence and foreign affairs.Subsidiarity is a founding principle of the EU.

In 1957 six core states founded the EU's predecessor, the European Economic Community. The remaining states have acceded in subsequent enlargements. On 1 July 2013 Croatia became the newest member state of the EU. In order to accede, a state must fulfill the economic and political requirements known as the Copenhagen criteria, which require a candidate to have a democratic, free market government together with the corresponding freedoms and institutions, and respect for the rule of law. Enlargement of the Union is also contingent upon the consent of all existing members and the candidate's adoption of the existing body of EU law, known as the Acquis communautaire.