By Efthymia Eleftheria Fotou and Francisca Costa Reis This blog post was written for the course "Current Issues in Global and EU Affairs", which took place from February 12-April 30, 2018. Since its early days NATO has been a cornerstone of both the transatlantic relationship and European defense. Now that the United Kingdom, one of NATO’s biggest advocates within the EU, is set to leave the Union, the question remains how Brexit will affect the transatlantic bond. Evaluating the possible impact of Brexit on European and transatlantic security, it seems unlikely that a British exit from NATO would occur. The accession of the United Kingdom to the EU was not made with a strong commitment to the CSDP, however London has always been willing to contribute to the North Atlantic Trade Organization, firstly because NATO's transatlantic dimension has always matched the geopolitical direction of London and secondly because membership in the Alliance secured the national sov