This essay is a contribution to the debate on the
implications of the recent decision of the CJEU in Slovak Republic v.
Achmea on investment arbitration under intra-EU BITs. This essay
critically examines the implications that the findings of the CJEU may have on
the validity of State consent to arbitrate under treaties as a matter of public
international law. The CJEU concluded that there is an inconsistency (or a
treaty conflict) between provisions of intra-EU bits containing an agreement to
arbitrate and provisions of the TFEU. The resolution of such a treaty conflict
in favour of the TFEU inevitably affects the validity of agreements to
arbitrate contained in intra-EU BITs. This essay considers the public international law rules on treaty
conflict, in particular, Article 30(3) of the VCLT, and concludes that this
provision’s requirement that conflicting treaties must deal with the same
subject matter, will become central in the analysis of any tribunal dealing
with the issue in the future. This requirement may serve as a lifeline for
investment arbitration in the aftermath of Slovak Republic v. Achmea. The essay also addresses the conflict provision of Article
351(1) of the TFEU to conclude that it is not applicable to the conflict with BITs,
and would thus not affect the validity of the consent to arbitrate contained in
intra-EU BITs.