The energy charter
treaty (ect) has given rise to major political and legal controversies for
years, culminating in the recent treaty exit of the european union (eu) and
some of its member states, while other member states remain parties to the
modernized ect. This reliance on different problem-solving strategies –
amendment, withdrawal, and interpretation or modification – showcases serious
coordination problems and legal difficulties that can arise when the eu and its
member states act together at the international level in the context of mixed
agreements. The article shows that the parallel pursuit of these strategies results
in a complex and fragmented web of legal relations among different eu member
states falling short of the goal to exclude all future intra-eu investment
arbitration under the ect. The identified legal limitations of the different
strategies would – by and large – also apply in extraeu relations, for instance
in case of inter se agreements with third countries aiming to exclude
investment arbitration under the ect.