The term ‘the EU’s three pillars’ is used to illustrate how the various forms of cooperation are built up within the EU depending on which policy area and which part of the treaty provisions is involved.

To demonstrate the differences between the various forms of cooperation within the three areas, even though the cooperation involved is within the same body, the EU, the structure of a typical Greek temple has been used as a basis, with each of the three pillars representing a different policy area. The three pillars are held together with a common roof and common foundations.�

The first pillar represents supranational cooperation. It is this cooperation which is derived from the EC Treaty, and it is within this cooperation that the EU can issue legislation, which directly bind EU citizens.�

Pillars 2 and 3 each contain a different type of intergovernmental cooperation. Pillar 2 represents foreign and security policy, while pillar 3 represents intergovernmental cooperation relating to police and judicial cooperation in criminal matters.

In the roof over the three pillars are the provisions that are common to the three policy areas, i.e. the provisions relating to the EU’s institutions – the Council, the Commission, etc. – which apply regardless of which policy area is concerned. The foundations for the three pillars are the provisions concerning amendment of the treaties, the admission of new members, etc.

The pillar structure is abolished in the new Constitutional Treaty, but special provisions concerning cooperation in the areas that are now covered by intergovernmental cooperation – the cooperation concerning the Common Foreign and Security Policy and that known as the area of freedom, security and justice (police cooperation, judicial cooperation in criminal matters, etc.) – are retained.