This article examines the use of the ‘national security argument’ in Swedish efforts to expand artificial intelligence (AI) use in law enforcement and its legal implications under EU law. Swedish authorities have invoked national security to justify the inapplicability of EU regulations, in a process of potential ‘concept creep’. However, the European Court of Justice (CJEU) has rejected similar broad interpretations of national security when such measures affect obligations under EU law. The article analyses the CJEU’s insistence on jurisdiction over measures undertaken in the national security context, and how its case law can be explained and characterized as a potential ‘competence creep’ challenging Member States’ attempts to bypass EU safeguards. It argues that national security-based exemptions are more viable when used by specialized intelligence agencies acting independently, but generally likely to fail when applied to broader or overlapping police functions subject to EU data protection law. Ultimately, the CJEU’s stance could potentially support EU legal protections by preventing Member States from expanding police use of AI under the guise of national security in the future, but it also reflects a broader struggle of competence between national governments and EU institutions which is likely to intensify.