The EU's decision-making process in general, and the co-decision procedure in particular, involve three main institutions:
- the European Parliament, which represents the EU's citizens and is directly elected by them;
- the Council of the European Union, which represents the individual member states;
- the European Commission, which seeks to uphold the interests of the Union as a whole.
The members of the European Parliament (MEPs) sit not in national blocks but in Europe-wide political groups that bring together all the main political parties operating in the EU member states.
Parliamentary elections are held every five years, and every EU citizen who is registered as a voter is entitled to vote. So Parliament expresses the democratic will of the Union's 374 million citizens, and it represents their interests in discussions with the other EU institutions.
The European Parliament works in France, Belgium and Luxembourg. The monthly plenary sessions, which all MEPs attend, are held in Strasbourg (France) - the Parliament's "seat". Parliamentary committee meetings and any additional plenary sessions are held in Brussels (Belgium), whilst Luxembourg is home to the administrative offices (the "General Secretariat").
Parliament has three main roles:
- It shares with the Council the power to legislate. The fact that is a directly-elected body helps guarantee the democratic legitimacy of European law.
- It exercises democratic supervision over all EU institutions, and in particular the Commission. It has the power to approve or reject the nomination of Commissioners, and it has the right to censure the Commission as a whole.
- It shares with the Council authority over the EU budget and can therefore influence EU spending. At the end of the procedure, it adopts or rejects the budget in its entirety.