Where Institutions Intersect: Analyzing Governance Seams in Hybrid Attacks on Critical Maritime Infrastructure

Hybrid attacks on critical infrastructure pose significant coordination problems for the European Union, NATO, and their member states. This article examines which governance seams come into play in attacks on maritime infrastructure in the Baltic Sea region and how the actors involved respond institutionally. The analytical basis for this article is provided by the hybrid threat model developed by Giannopoulos, Smith, and Theocharidou, which systematizes actors, domains, tools, and escalation phases of hybrid activities. Methodologically, the study follows a case-study approach using congruence analysis, following Blatter and Haverland. The data are drawn from ten coded documentary and analytical sources, including EU Council recommendations, official government statements, NATO documents on underwater infrastructure, and UN Security Council records. The analysis supports all four theoretically derived assumptions: governance seams become salient at the intersections of civil and military responsibilities, national and supranational levels, political rhetoric and operational capacity, and public accountability and intelligence confidentiality. The documented institutional responses primarily address operational aspects without resolving the underlying structural problems. The results indicate that these governance seams are structural in nature and can mutually reinforce each other.