ENSince the end of the East-West conflict, various intergovernmental and transnational organizations have collectively governed the Baltic Sea Region. Exploring key features of the organizational architecture of three such organizations – HELCOM, the Council of the Baltic Sea States, and the Union of Baltic Cities – we ask how their institutions evolved in the aftermath of critical junctures affecting the region over the past three decades. Findings show that specific-purpose organizations are robust with respect to changes than general-purpose organizations whereas general-purpose maybe less so. With growing geopolitical tensions and global turbulence, this finding holds lessons for the design of transnational cooperation in the future – and beyond the Baltic Sea Region. Keywords: Critical juncture; transnational organizations; Baltic Sea cooperation; Council of the Baltic Sea States (CBSS); European Union; Helsinki Commission; Union Of Baltic Cities (UBC); Russia. [From the publication]