Why, despite its longstanding identity as a non-aligned country, did Sweden apply for NATO membership in May 2022? Did this decision not fundamentally challenge Swedish ontological security? Conversely, could a desire to maintain ontological security somehow explain the radical policy shift? This article conceptualises the state’s self in terms of layered identity constructions, some of which are more deeply embedded while others are relatively fleeting and superficial. When these clash, the latter may have to change in order to maintain some stability in the more sedimented layers. This theoretical perspective provides insight into the empirical puzzle. The article argues that non-alignment was a relatively more superficial Swedish identity construct in the early months of 2022 than previously recognised. It finds that following Russia’s full-scale invasion of Ukraine and Finland’s decision to join NATO, non-alignment began to conflict with more entrenched Swedish identity constructs, thereby jeopardising the stability of the Swedish self. While Sweden’s decision to join NATO did produce ontological insecurities in parts of the population, the article concludes that the policy shift helped to restore some ontological security for those Swedes who adhere to now-dominant identity narratives.