BRUSSELS – At 751 members, the European Parliament is larger than the U.S. Congress or British House of Commons, but has far less legislative muscle.
The European Union's only popularly elected institution, it shares power over the EU budget and legislation with the Council of the European Union, which directly represents the governments of the bloc's 28 member states.
The parliament has to approve EU-wide legislation on issues including the internal market, environment, transport, agriculture, consumer protection and civil liberties. It also exercises oversight over how EU institutions spend taxpayers' money.
But it cannot levy taxes or legislate in certain areas and, in practice, member governments of the EU play a much greater role in areas like foreign policy, security and defense, health, education and social policy.
This month's election marks the first time where, under the 2009 Lisbon Treaty, European voters' choices are supposed to be taken into account when the president of the EU's executive arm, the European Commission, is chosen. How that will work in practice remains to be seen. But even if member states try to impose a candidate, he or she must be ratified by a majority of the parliament.
Voting begins Thursday in Britain and the Netherlands. On Friday it's Ireland's turn. Latvia, Malta and Slovakia vote on Saturday, while people in the Czech Republic may cast ballots Friday or Saturday. Sunday is election day in the rest of the EU, with results from all countries being made public after the last polling stations close in Italy at 11 p.m. (2100 GMT).
There have been 766 members of the European Parliament (also known as MEPs) since Croatia joined the European Union in July. The number of seats in the parliament, which is based in Brussels and the French city of Strasbourg, has been limited in the future to 751.
Seats are allocated according to member states' populations. Tiny states like Malta have six and Germany has the most — 96.