Abstract
This paper examines the European Union’s decision to withdraw from the Energy Charter Treaty and its refusal to endorse the modernised version, focusing on its legal implications under both EU and international law. The analysis explores whether the EU’s actions align with its obligations under Article 21 of the Treaty on European Union and the Vienna Convention on the Law of Treaties, particularly regarding the principles of good faith and pacta sunt servanda. It considers the tension between the EU's commitment to international investment protection and its ambitious climate goals. The paper also investigates how these legal challenges affect the EU's role in global energy governance and treaty negotiations, offering insights into the broader implications of balancing political, environmental, and legal priorities in future multilateral agreements.