The Withdrawal from International Organisations and the Reversibility of the European Integration

The withdrawal from the international treaties is regulated by the Vienna Convention on the Law of Treaties of 1929 and by the customary international law. It liberates the State that exercises this right from the obligation to execute the treaty. In the case of treaties establishing international organizations, the withdrawing State terminates its membership, as it happened in 1965 when Indonesia addressed a notice of withdrawal to the Secretary-General of the United Nations (although one year after the cooperation was re-launched).

The legal instrument of withdrawal has been thoroughly studied in the past, but today is attracting new interest as a consequence of the Brexit: the decision to withdraw from the European Union expressed by the British population through the referendum of June 2016 has opened the door to an unprecedented scenario.

As a tremble running through the Union, the Brexit forces the European policy-makers and the European populations to acknowledge the problem of a sustainable integration and urges for a renovated debate on the changes needed in the Union in order to give new impetus to the project.

To do that, it seems opportune to determine to what extent this withdrawal differs from what occurred in the past. What are its implications? How can we measure its consequences? This paper aims to provide a comprehensive analysis of the legal framework and to contribute to the debate on the perspectives of the future relations between the UK and the EU, as well as among the 27 EU’s Member States.