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.