Defence Policy (CSDP) occupy a unique space in EU governance. Both policies have supranational elements, yet their formally intergovernmental status shields them from the increased scrutiny powers granted to national parliaments after Lisbon. National parliamentary scrutiny of these policy areas has thus received relatively little attention. Using an analytical framework of 'authority, ability and attitude', this paper argues that attitude, meaning MPs' willingness to scrutinise CFSP, is the most important factor in explaining the empirical variation in the quantity and quality of national parliamentary scrutiny of CFSP. Drawing on qualitative research and interviews conducted as part of the OPAL project, the paper demonstrates that formal powers do not, in practice, equate to 'strong' scrutiny, arguing that the strongest parliaments are those that make CFSP scrutiny a systematic, normalised and culturally accepted part of parliamentarians' everyday work.The EU's Common Foreign and Security Policy (CFSP) and Common Security and Defence Policy (CSDP) are situated at the nexus of two fields that have generally proven problematic for parliamentary scrutiny: foreign and security policy, and EU integration. Many European legislatures have long treated foreign policy as a matter for executive competence, having limited involvement in policy-making and weak scrutiny mechanisms relative to other fields. This problem is often exacerbated in CFSP/CSDP, where policy-making takes place at a level even further removed from national parliaments. The cases of CFSP and CSDP thus provide special insight into how national parliaments oversee non-legislative aspects of EU policy, in which scrutiny activity may be more ad hoc, less automatic, and less institutionalised than it is for EU legislation. Essentially, these policy areas pose the question: if national parliaments are not required automatically to scrutinise an aspect of EU policy, will they do so anyway, and under what circumstances?