Joining the European Union is one of the longest application processes in international politics. It has taken past applicants anywhere from a few years to several decades, and the path is defined as much by politics as by paperwork.
The Copenhagen criteria
Any European country may apply, but membership requires meeting the Copenhagen criteria: stable institutions guaranteeing democracy and the rule of law, a functioning market economy able to cope with competition inside the single market, and the capacity to take on the obligations of membership.
Candidate status and negotiations
After a country applies, the Commission issues an opinion and member states decide unanimously whether to grant candidate status. Actual negotiations are organised into 35 thematic chapters covering everything from food safety to judicial reform. Each chapter is opened and closed only with the agreement of every member state, which gives each capital repeated opportunities to slow or pause the process.
The final steps
When all chapters are closed, an accession treaty is signed and must be ratified by every member state and the applicant, in most countries by parliament and in some by referendum. Only then does the applicant become a member.
Why the process matters beyond the applicants
Enlargement has been described as the EU’s most successful foreign policy: the prospect of membership has driven far-reaching reforms across the continent. It also raises hard internal questions for the Union itself, from budget shares to how many commissioners and MEPs an enlarged EU should have.