<p><b>Should the European Union regulate criminal justice? This open access book explores the question forensically establishing whether a compelling normative justification for EU action in the field exists.</b> <p/>It develops an integrated standard based on the perspectives of the effective allocation of regulatory authority between the EU and the Member States representation-based political theories and harm-based theories of criminal law. This is a work that will be welcomed not only by EU criminal law scholars but also by practitioners judges and policymakers.</p>