Elections to the European Parliament (EP) are rapidly approaching, with EU citizens taking to the polls from 4-7 June, the date dependant on the typical voting day in each country. The vast majority of the parliamentarians (MEPs) will be elected on 7 June, when about 80% of the members will be elected.
The EP is a unique institution, more powerful than many legislatures in its ability to set transnational policy, but weak because it cannot set its own agenda. Proposed policy changes are submitted to the EP for debate and approval or refusal, rather than the parliament being able to introduce legislation on its own.
Along with the European Commission (executive branch-type activities) and the European Council (oversight activities by top authorities from each member state), over 700 MEPs of the EP represent the interests of more than 200 political parties in the 27 EU states. Every five years since direct election began in 1979, voters in each member state have elected MEPs from national parties through the local electoral system, most often the “Party List” method. National parties then associate with pan-European parties that create voting blocs in the EP.
Power in the EP, as with most parliamentary systems, is concentrated through coalition-building between various parties in order to generate a bloc large enough to control the passage of legislation. Currently the marriage between the European People’s Party and the European Democrats (EPP-ED) controls the largest bloc of MEPs, with 288 of the 785 members. A center-right group, EPP-ED is made up of mainline conservatives, such as France’s UMP, led by President Sarkozy, Germany’s Christian Democrats, the party of Chancellor Merkel, and the UK’s Conservatives, led by David Cameron. Second largest, the Party of European Socialists (PES) currently holds 217 seats, and represents the center-left wing. The Socialist and Labour parties of most EU states fall into this coalition, such as Labour in the UK or the French Partie Socialist. Six other coalition parties follow the top two parties, but none with more than 12.7% of the parliamentary votes (a good summary here).
http://www.fivethirtyeight.com/2009/05/introduction-to-european-parliament.html#comments