This article looks at the collective acts of the Member States which have a
close connection with the EU, either because they trigger action at EU
level, or because they find their basis in the Treaties. It is argued that such
acts should not escape review just because they are not clearly situated
within either the EU or the domestic legal system. The article identifies
five categories of such acts, and then focuses on the EU-Turkey Statement
and Sharpston cases as examples. For collective acts not based on the
Treaties, various factors determine whether or not they are ascribable
only to the collective action of Member States, or rather are adopted
jointly with the EU institutions. If an act is also ascribable to an EU
institution it must not escape judicial review, either through Article 263
TFEU or via preliminary rulings. Furthermore, EU acts deriving from a
collective decision are subject to judicial review at EU level, and if an EU
institution participated in the adoption of such acts, or failed to ensure
that the act complied with EU primary law, the EU might incur
non-contractual liability. Collective acts of the Member States can
produce legal effect in the EU legal system only insofar as based on the
Treaties and such acts have primary law status only when ratified
according to national constitutional requirements. Acts lacking primary
law status must be subject to the jurisdiction of the ECJ regarding their
compatibility with the Treaties and the Charter.