Discussion: Reconciling Decentralized Enforcement with European Harmonization
The operational reality of the General Data Protection Regulation (GDPR) One-Stop-Shop (OSS) mechanism demonstrates an ongoing tension between supranational harmonization and proactive national supervision. As observed in administrative practice, procedural complexity within cross-border cooperation frameworks can inadvertently compromise swift enforcement, creating administrative friction among supervisory authorities (European Union, 2026). Within this multi-level governance architecture, the Belgian Data Protection Authority (APD/GBA) exemplifies how a domestic regulator can operate as a critical gatekeeper rather than a passive conduit for lead supervisory authorities. By actively scrutinizing cross-border digital architectures and standardized industry practices—most notably in complex sectors such as online behavioral advertising (Belgian Data Protection Authority Ruling, 2022)—the Belgian authority challenges the assumption that lead authorities hold exclusive analytical dominance over transnational processing activities. Furthermore, this assertive posture extends to emerging technological paradigms, where domestic guidance on artificial intelligence addresses core accountability gaps before centralized EU-wide consensus fully consolidates (Belgian Data Protection Authority, 2025). Consequently, the Belgian DPA's strategic interventions illustrate that decentralized gatekeeping is essential for testing the boundaries of European data protection jurisprudence. However, this decentralized assertiveness also underscores the structural vulnerability of the OSS mechanism: when national supervisory authorities adopt diverging procedural pathways or substantive interpretations, the overarching goal of uniform enforcement risks being constrained by prolonged institutional deliberation.