Withdrawal from the European Union

Withdrawal from the European Union is the legal and political process whereby an EU member state ceases to be a member of the Union. Article 50 of the Treaty on European Union (TEU) states that "Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements". 

As of February 2019, no member state has withdrawn from the EU (or the EC); however, the Government of the United Kingdom triggered Article 50 to begin the UK's withdrawal from the EU in March 2017 following a referendum, and the withdrawal is scheduled in law to occur on 29 March 2019. 

Three territories of EU member states have withdrawn: French Algeria (in 1962, upon independence), Greenland (in 1985, following a referendum) and Saint Barthélemy (in 2012), the latter two becoming Overseas Countries and Territories of the European Union. 

Background 

The states who were set to accede to the EU in 2004 pushed for an  exit right during the 2002-2003 European Convention. The acceding states wanted the option to exit the EU in the event that EU membership would adversely affect them. During negotiations, eurosceptic states such as the UK and Denmark subsequently pushed for the creation of Article 50. 

Article 50, which allows a member state to withdraw, was originally drafted by Scottish cross-bench peer former diplomat Lord Kerr of Kinlochard, the secretary-general of the European Convention, which drafted the Constitutional Treaty for the European Union. Following the failure of the ratification process for the European Constitution, the clause was incorporated into the Treaty of Lisbon which entered into force in 2009.

Prior to this, no provision in the treaties or law of the EU outlined the ability of a state to voluntarily withdraw from the EU. The absence of such a provision made withdrawal technically difficult but not impossible. Legally there were two interpretations of whether a state could leave. The first, that sovereign states have a right to withdraw from their international commitments; and the second, the treaties are for an unlimited period, with not provision for withdrawal and calling for an "ever closer union" - such commitment to unification is incompatible with a unilateral withdrawal. The Vienna Convention on the Law of Treaties states where a party wants to withdraw unilaterally from a treaty that is silent on secession, there are only two cases where withdrawal is allowed: where all parties recognize an informal right to do so and where the situation has changed so drastically, that the obligations of a signatory have been radically transformed. 

Procedure 

Article 50 of the Treaty on European Union, enacted by the Treaty of Lisbon on 1 December 2009, introduced for the first time a procedure for a member state to withdraw voluntarily from the EU. The article states that: 

1. Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements. 
2. A Member State which decides to withdraw shall notify the European Council of its intention. In the light of the guidelines provided by the European Council, the Union shall negotiate and conclude an agreement with that State, setting out the arrangements for its withdrawal, taking account of the framework for its future relationship with the Union. That agreement shall be negotiated in accordance with Article 218(3) of the Treaty on the Functioning of the European Union. It shall be concluded on behalf of the Union by he Council [of the European Union], acting by a qualified majority, after obtaining the consent of the European Parliament. 
3. The Treaties shall cease to apply to the State in question from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification referred to in paragraph 2, unless the European Council, in agreement with the Member State concerned, unanimously decides to extend this period. 
4. For the purposes of paragraphs 2 and 3, the member of the European Council or of the Council representing the withdrawing Member State shall not participate in the discussions of the European Council or Council or in decisions concerning it.
5. If a State which has withdrawn from the Union asks o rejoin, its request shall be subject to the procedure referred to in Article 49.

This provision does not cover certain overseas territories which under TFEU Article 355 do not require a full treaty revision. 

Invocation

Thus, once a member state has notified the European Council of its intention to leave, a period begins during which a withdrawal agreement is negotiated, setting out the arrangements for the withdrawal and outlining the country's future relationship with the Union. Commencing the process is up to the member state that intends to leave. 

The article allows for a negotiated withdrawal, due to the complexities of leaving the EU. However, it does include in it a strong implication of a unilateral right to withdraw. This is through the fact that a state would decide to withdraw "in accordance with its own constitutional requirements" and that the end of the treaties' application in a member state that intends to withdraw is not dependent on any agreement being reached (it would occur after two years regardless). 

Negotiation

The treaties cease to apply to the member state concerned on the entry into force of the withdrawal agreement or, in the absence of such an agreement, two years after the member state notified the European Council of its intention to leave, although this period can be extended by unanimous agreement of the European Council. 

The leaving agreement is negotiated on behalf of the EU by the European Commission on the basis of a mandate given by the remaining Member States, meeting in the Council of the European Union. It must set out the arrangements for withdrawal, taking account of the framework for the member state's future relationship with the EU, though without itself settling that framework. The agreement is to be approved on the EU side by the Council of the EU, acting by qualified majority, after obtaining the consent of the European Parliament. For the agreement to pass the Council of the EU it needs to be approved by at least 72 percent of the continuing member states representing at least 65 percent of their population. 

The agreement is concluded on behalf of the Union by the Council and must set out the arrangements for withdrawal, including a framework for the State's future relationship with the Union, negotiated in accordance with Article 218(3) of the Treaty on the Functioning of the European Union. The agreement is to be approved by the Council, acting by qualified majority, after obtaining the consent of the European Parliament. Should a former Member State seek to rejoin the European Union, it would be subject to the same conditions as any other applicant country. 

Remaining members of the EU would need to manage consequential changes over the EU's budgets, voting allocations and policies brought about by the withdrawal of any member state.