The Maastricht treaty (formally, the Treaty on European Union) which was negotiated between the members of the European Community, led to the creation of the European Union. It was the result of separate negotiations on monetary union and on political union.
The treaty led to the creation of the Euro, and introduced the three-pillar structure (the Community pillar, the Common Foreign and Security Policy or CFSP pillar, and the Justice and Home Affairs pillar). The CFSP pillar was built on the foundation of European Political Cooperation (EPC), but brought it under a treaty and extended it. The JHA pillar introduced cooperation in law enforcement, criminal justice, civil judicial matters, and asylum and immigration.
Originally, the European Community (EC) dealt mainly with economic and trade matters. The European Commission and the European Court of Justice, both independent from the EC governments, had a lot of power within the system. The European Parliament, which was directly elected by the citizens of the EC member states, also had some power. The Governments controlled the remainder of the power, but since the mid-1980s had increasingly been doing so through majority votes. This system was called the Community method, or supranationalism, since international institutions not directly controlled by the governments wielded a lot of power, and members could have decisions they disagreed with imposed upon them through majority votes.
It was desired to add competencies in foreign policy, military and criminal matters to the European Community. However, many member states considered that these areas were too sensitive to be managed by the mechanisms of the European Community, and that the power of governments in relation to these areas had to be stronger than the powers of governments in the European Community. That is, an intergovernmental, as opposed to supranational, system would have to be used. Other member states feared that this might threaten the power of the independent supranational institutions (the European Commission, European Court of Justice and European Parliament) in relation to the economic matters then dealt with by the European Community. The three pillar structure was then developed to isolate the traditional Community responsibilities in the area of the economy (the Community Pillar) from the new competencies in the areas of foreign policy and military matters (the CFSP pillar) and criminal matters (the JHA pillar).
The Maastricht treaty was signed on February 7, 1992 at Maastricht in the Netherlands, where the final negotiations had taken place during December 1991. The treaty entered into force November 1, 1993 and has been amended to a degree by later treaties.