LAUSR

Abstract Since Russia’s military intervention in Ukraine in 2014, the security situation of Europe’s eastern ‘frontline states’ has undergone significant changes. In and around the Black Sea, the Baltic Sea and the Barents Sea, the scope and scale of military activity has grown, as has the frequency of Russian–Western military encounters. Despite the many similarities between the three regions, and despite the increased risk of negative spillover from one region to another, there are also noteworthy regional differences. As of today, the security challenges appear to be more severe and pressing in the southern and central part of the ‘frontline’ than in the northern.