Proving Public Interest: The Growing Impact of Evidence in Free Movement Case Law

When national measures restrict free movement rights, Member States can argue that their actions are,nevertheless, justifiable and proportionate. But how do they actually demonstrate this? This article explores the standard that Member States must satisfy to prove their public interest claims successfully. It will be argued that a critical information gap on what the Court of Justice expects defendant States to establish has been narrowed through a more concerted focus on proof in recent case law; but that significant issues still demand further attention. While an evolving guidance framework can be pieced together by extracting key principles from relevant - especially more recent - case law, it is questionable whether this is sufficient for national courts and lawyers. The fact that more attention is being placed on proof and evidence in recent case law, however, also raises questions about the value or even propriety of applying a veneer of empiricism over the many complexities involved in adjudicating on public interest choices. As a case study, the article discusses the difficulty of unpicking economic arguments from public interest claims. It is suggested, overall, that knowing an appropriate standard of proof has to be reached is one thing; but knowing what it is and how to reach it is something else entirely.