The Distinction between Intra-EU and Extra-EU BITS made by the CJEU in Achmea Case and Opinion 1/17 and the Conflict of ISDS with the Principle of Autonomy of EU Law

Abstract

Over the past years, the principle of autonomy has played a crucial role in
the fields of the EU’s external relations and investment law. The importance
of this principle, the basic concepts and aspects of which are discussed be-
low, is evident in the attempt to delineate the relationship and interaction be-
tween EU law and investment arbitration. The relationship between interna-
tional investment law and EU law has been characterised by the legal theory
as “a stormy one” while the definition of the status and the effect of the latter
both in intra and extra-EU investment arbitration has emerged as a complex
and thought-provoking issue.