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A Guide to EU Enlargement

In the 1950s, the leaders of six countries recovering from World War II came together to foster peace, prosperity and European values on the continent. Belgium, France, Italy, Luxembourg, the Netherlands, and West Germany were the founding members of the European Economic Community, which is now known as the European Union (EU).

The EU benefits the interests of Member States and acceding countries. Through enlargement, it creates a prosperous internal market, and it makes Europe a safer place through the promotion of democracy and fundamental freedoms.

Who can join?

Under the Treaty of the European Union, any European state is eligible to apply for membership if it is committed to promoting the democratic values of the EU.

The initial conditions for membership are:

  • Complying with all of the EU’s standards and rules
  • Receiving consent from the EU Member States and its institutions
  • Obtaining consent from its citizens, which has been approved through the national parliament or by referendum.

Once the country wishing the join the EU has met the criteria for accession, they must meet the terms defined by the Copenhagen criteria. Candidate countries must have:

  • Stable institutions ensuring democracy, the rule of law, human rights and respect for, and the protection of minorities
  • A functioning market economy with the capacity to handle the EU’s competition and market force
  • The ability to effectively undertake and implement the obligations of membership, in addition to the adherence of the intents of political, economic and monetary union


The Process

Before an applicant country can sign a pre-accession agreement, it typically signs an association agreement. The purpose of this is to help prepare the country for candidacy and successful negotiations for membership.

Once a formal application for EU membership is submitted, the Council of the European Union requests that the European Commission prepare an opinion on the state’s readiness.

The Commission and the candidate country will individually examine its laws. If there are any inconsistencies with EU law, the Council will advise opening negotiations in certain policy areas that are divided into 35 different policy fields, known as ‘chapters’. When a state is considered ready, the screening process and negotiation can begin.

 Negotiations concern the candidate country’s ability to convince the EU that it can assume the obligations of membership and execute European law. A chapter can be closed when both sides can agree that it has been executed appropriately. The Commission has the authority to reopen a chapter at any time if it believes that the candidate country has fallen out of compliance with a policy area.

Once the negotiation process is complete, and all chapters have been closed, a treaty of accession will be signed. In order for the applicant to successfully reach full membership, all EU member states and the institutions must ratify the treaty. This can easily take up to a decade to complete.

The overall outlook for successful enlargement is to safeguard the democracy and stability of Europe as a whole. By defending these values, the EU aims to respect and preserve diversity and the freedom of movement. EU enlargement map

A visual representation of all current EU Member States, and Candidate Countries by date of accession is available here.

Sandra Song
Sandra is a Research Analyst at the NATO Association of Canada. She was the former Editor for the Canadian Armed Forces program, and she was previously a Junior Research Fellow for the Strategic Reserve Program in 2013. Sandra has a BA Bilingual Hons. in International Studies from Glendon College, York University. She recently completed her MA in International Conflict & Security at the University of Kent, Brussels School of International Studies. Her dissertation examined the political and legal perspectives of balancing security and liberty in the case of civilian aircraft hijackings that would be used as a weapon for terrorism. Prior to her time at the NAOC, Sandra was contracted as an Ocean Energy Plan Project Consultant for a non-profit organization in Belgium and the Netherlands.