Any country that satisfies the conditions for membership can apply. These conditions are known as the ‘Copenhagen criteria’ and include a free-market economy, a stable democracy and the rule of law, and the acceptance of all EU legislation, including of the euro.
A country wishing to join the EU submits a membership application to the Council, which asks the Commission to assess the applicant’s ability to meet the Copenhagen criteria. If the Commission’s opinion is positive, the Council must then agree upon a negotiating mandate. Negotiations are then formally opened on a subject-by-subject basis.
Due to the huge volume of EU rules and regulations each candidate country must adopt as national law, the negotiations take time to complete. The candidates are supported financially, administratively and technically during this pre-accession period.