To Err Twice

Utilizing the tension between EU and prisons as case study, this article argues for the necessity of a multidisciplinary EU methodological framework. To address the threat of cross-border criminality, the legal principle of mutual trust has been placed at the core of EU judicial cooperation mechanisms. Mutual trust translates to the presumption of equivalent rights protection, a presumption extending to detention, and on the basis of legal standards comprising the pan-EU penal imaginary. Yet, in light of disparate and inadequate detention regimes, mutual trust proves legal fiction. Consequently, and by ignoring the operation of law in action, the Union has exposed itself to the challenge of regulating and effectively enforcing individual standards in prison. To this end, following a doctrinal approach, EU scholars and institutions advocate for further harmonization of detention at EU level. This article argues that such a motion suffers two methodological shortcomings. Firstly, EU scholarship overly underscores the legal dimension of the issue, too readily framing the problematic situation of detention as a legal problem to be redressed via legislative recourse. Secondly, calls for legal harmonization underestimate the political nature of law as policy, and the perils of perceived (horizontal or vertical) illegitimacy of any legally binding intervention. Framing its enquiry by reference to the question posed in this special issue, the article concludes that, while black-letter research in EU law remains essential, novel challenges and idiosyncrasies of the acquis communautaire demand an evolved methodological toolbox, to better reflect the inherent interdisciplinarity of prison policy in the AFSJ.