Today, the attribution in multi-actor settings can no longer be exclusively considered under the 2001 ARSIWA and the 2011 ARIO. In this chapter, we consider how human rights and refugee law violations in the framework of migration cooperation might entail responsibility attribution to the involved actors under an emerging framework of rules. This novel framework takes the systemic completeness of international law as a baseline. It consists of the 2020 Guiding Principles on Shared Responsibility in International Law, the critiques of attribution by scholars and arguments from justice. ‘Systemic responsibility attribution’ is the label we use for it, and EU migration arrangements with Türkiye, Tunisia, Serbia and Niger provide the context for showcasing the application of this framework. We analyse the containment of refugee movements in cases related to all four countries. While systemic responsibility attribution is grounded on ILC articles in the case of Türkiye and Tunisia, Principle 7 GPRSIL offered a pathway towards attribution for Niger, in parallel to an attribution argument drawing on arguments from justice. In the case of Serbia, the sole avenue for an attribution argument were arguments from justice. Neither ILC articles nor the GPSRIL offered stepping stones for responsibility attribution for cooperation with Serbia.