Originally, the European Parliament had little political power or authority. But, after the Treaty of Lisbon came into force in December of 2009, the Parliament has robust decision making authority. The European Parliament shares legislative power equally with the Council of the European Union. This means it is empowered to adopt European laws (directives, regulations etc,). It can accept, amend or reject the content of European legislation. The Parliament has no authority to propose legislation directly, but may request the European Commission to propose legislation.
This political assembly of 705 members is directly elected by the citizens of the 27 EU Member States. Representation is roughly proportional to the population of the EU Member States. Members of the European Parliament are sometimes referred to as MEP's.