The European Union is a supranational political and economic union whose Wikipedia article states it comprises twenty seven member states: Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain and Sweden, established by the Maastricht Treaty in 1993. Each member state listed under this group is grouped here because its own founding or currently governing constitution belongs to one of the twenty seven states that article names as EU members, a defined and closed intergovernmental membership rather than a broader continental or cultural grouping. This class distinguishes these twenty seven states' current foundational legal instruments from the constitutions of European states that are not EU members, and from constitutions grouped elsewhere in this atlas under other regional or organizational schemes, including historic constitutions of EU member states that predate accession. Each member placed under this group carries its own separate citation for the specific fact that its country belongs to the European Union.