Is the Baltic Sea a NATO Lake? John R. Deni This article is part of the Baltic Sea Region Security Initiative developed by the Carnegie Endowment’s Europe Program. With the addition of Finland and soon Sweden into the NATO fold, nearly all of the Baltic Sea littoral states will be alliance members. This has prompted some observers to label the Baltic Sea a kind of “NATO lake.” This is unfortunate framing that implies the Baltic is NATO’s alone, that the Western alliance has little to worry about from a security perspective, or that the littoral states can lean back and rest in the warm embrace of Article 5 and the United States’ commitment to their security. This, of course, does not reflect reality, underlined recently by suspicious damage to the Baltic Connector gas pipeline and telecom links. The fact remains that, today, the Baltic littoral states face a number of significant threats that membership in NATO alone will not ameliorate. Instead, the members of the alliance on the Baltic Sea—Finland, Estonia, Latvia, Lithuania, Poland, Germany, and Denmark, as well as aspirant Sweden—and the United States confront a dynamic regional security picture that will require further refinement of capabilities and increased capacity as well as more considered efforts in collective cooperation through both NATO and the European Union.