Undersea deterrence in the Baltic: NATO’s evolving protection of critical infrastructure

This paper examines NATO’s evolving deterrence posture toward critical undersea infrastructure in the Baltic Sea after the 2022 Nord Stream sabotage. It asks why NATO’s post-2022 initiatives have produced uneven outcomes across pipelines and subsea data cables. Drawing on deterrence theory, it analyzes the Nord Stream, Balticconnector, C-Lion1, and EstLink 2 related disruptions. It argues that NATO’s response has generated selective and layered deterrence – stronger around fixed, politically salient pipelines, but weaker against dispersed cables where attribution, legal ambiguity, and monitoring challenges persist. The study concludes that undersea deterrence now depends more on resilience, surveillance, attribution, and coordinated presence.