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.