Along with the Council of Ministers, the EP constitutes the EU's legislature. Historically, the EP was purely a consultative body, but treaty changes have given it more and more power to amend and block legislation.
When a proposal is referred to the EP, it develops and declares an 'opinion' – which has differing degrees of force depending on the procedure in use.
The first stage of this process is referral of the proposal to the relevant committee. Where a proposal crosses over committee mandate areas, up to three may be asked for their views, but only one will be named as the responsible committee which draws up the report that is submitted to the plenary session.
A principal spokesperson for the inquiry is chosen (on the basis of inter-party negotiations) by the committee, who is known as the rapporteur. The rapporteur takes the lead in the preparation of a first draft of the report, which is considered the committee as a whole – and is either passed back for amendment or approved for referral to the plenary session.
The extent of discussion required to agree upon a report depends upon the complexity of the proposal under consideration, the controversy it generates and the positions of the members of the committee.
The agreed report is then presented to the plenary session of the EP and given a 'first reading' by the rapporteur, who explains the report and any amendments proposed, and gives the committee's position on any other amendments proposed by MEPs from outside the committee. The rapporteur is often asked to guide the EP in the event that the commission indicates its willingness to accept some but not all of the amendments proposed.
The EP then votes to adopt or reject the opinion recommended by the committee, and its decision is passed back to the other institutions. What happens at this point depends on which procedure is being followed.
The council usually provides its common position after the first reading.