The adjudication of claims concerning the enforcement of annulled international arbitral awards—both under the ICSID framework and within various national legal systems—remains one of the most contentious issues in contemporary international law. Notwithstanding the divergence in the approaches adopted by different jurisdictions, the phrasing of Articles V and VII of the New York Convention on the recognition and enforcement of foreign arbitral awards is characterized by a significant lack of clarity. Given the inconsistency in judicial decisions and the imperative to examine the theoretical foundations underpinning these conflicting interpretations, this article seeks to answer a fundamental question: What approach do national courts adopt when confronted with annulled arbitral awards? Utilizing a comprehensive literature review and a qualitative methodology, the authors analyze the competing theories of "nationalization" and "denationalization" of awards, while highlighting the ambiguities inherent in the New York Convention. The findings of this research demonstrate that, beyond the opacity of ICSID regulations, the disparate theoretical perspectives on the nexus between the arbitral process and the law of the seat constitute the primary drivers of the lack of uniformity in the enforcement of annulled international arbitral awards.