Evolution of the European Union: Key Treaties and Enlargements

Key EU Treaties: SEA, Maastricht, Amsterdam, Nice

The founding treaties of the European Union were amended with two distinct purposes:

• Horizontal Extension: To increase the number of Member States.
• Vertical Extension: To increase the number of powers transferred to the communities.

A major reform in this regard resulted from two pivotal treaties, effectively forming a single, comprehensive reform: the Single European Act (SEA) of 1986 and the Treaty on European Union (TEU) of 1992. This period marked a significant turning point for the European Union. These treaties not only increased and strengthened the powers of economic integration but also introduced political cooperation, all wrapped up in the newly formed EU. This represented a substantial quantum leap, as political cooperation was formally introduced alongside economic integration.

The Single European Act (SEA) and its Legacy

The Single European Act was a treaty through which Member States agreed upon various measures to improve the internal market. Key among these was the commitment to create an economic and monetary union. Furthermore, the SEA laid the foundations for future political cooperation in both foreign and domestic policy. This treaty was thus instrumental in paving the way for the subsequent Treaty on European Union, signed in Maastricht on February 7, 1992, and subsequently known as the Maastricht Treaty.

The Treaty on European Union (Maastricht Treaty)

The Treaty on European Union (TEU) was a 'treaty of treaties,' consolidating existing treaties and establishing initial and final provisions applicable to all. It significantly expanded the scope of European integration by introducing political cooperation, both internally and externally. The TEU integrated the following components:

• Initial Provisions
• Treaty establishing the European Economic Community (EEC)
• Treaty establishing the European Coal and Steel Community (ECSC)
• Treaty establishing the European Atomic Energy Community (Euratom)
• Political integration, encompassing both internal affairs and European citizenship
• External affairs provisions
• Final Provisions

This comprehensive framework, known as the Treaty on European Union, transcended the economic sphere to enter the political arena. It introduced European citizenship within the European Community Treaty and included provisions on foreign policy, security policy, and cooperation in the fields of justice and home affairs. The TEU was subsequently amended first by the Treaty of Amsterdam on October 2, 1997, and secondly by the Treaty of Nice on February 26, 2001.

EU Enlargement: Post-1986 Expansions

Following 1986, the European Union underwent significant enlargements:

• 1995: Austria, Finland, and Sweden were admitted. Norway, however, rejected membership in a referendum.
• 2004: Cyprus, Slovakia, Slovenia, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, and the Czech Republic joined. While these states generally had democratic systems and market economies, the subsequent 2004 enlargement proved more complex. In 1998, 13 states, many with different historical and economic backgrounds from Western Europe, applied to join, initiating a significant enlargement process.
• 2007: Bulgaria and Romania were admitted.