The changes undergoing global energy markets and the structure of the world economy over the past decade have placed the EU in a growingly unfavourable situation. A good illustration of this is the crisis experienced by the Energy Charter Treaty (ECT). This EU-sponsored international regime, born with the favourable winds of the immediate post-cold war, experienced growing difficulties throughout the 2000s, leading the institution to a standstill after the withdrawal of Russia in 2009. This paper looks at the EU’s role in the ECT over the last decade, enquiring into how it has dealt with a growingly unfavourable context for its ability to exert influence. By combining Robert Cox’ work on international structures and Walter Carlsnaes’ approach to foreign policy analysis, the paper finds that, against all expectations, the EU has chosen the path of entrenchment over accommodation. The paper thus seeks to explain this seemingly puzzling foreign-policy choice.