This article is part of the Baltic Sea Region Security Initiative developed by the Carnegie Endowment’s Europe Program.
With the recent accession of Finland to NATO and Sweden prospectively following suit, the military alliance is set to expand northward. Helsinki and Stockholm have long been steadfast military and political partners in the region, closely interoperating with NATO members for many years. In addition, they field some of the most modern, well-equipped militaries in Europe, with whole-of-society defense mentalities and competitive defense industrial bases.
Major media outlets in the United States and Europe quickly welcomed this change as turning the Baltic Sea into a “NATO lake.” Rebuttals were few, but this is a potentially dangerous, misleading interpretation. At best, it amounts to uncritical self-cheerleading; at worst, it is a self-delusion that could lead to real military and geopolitical consequences.
The Sticky Problem With Analogies
Shorthand such as “NATO lake” is not new or exclusive to Northern Europe. Past senior officials like German vice admiral Friedrich Ruge, the first commander of the post–World War II Bundesmarine, fell prey to the same oversimplified thinking. Ruge referred to the North Atlantic as “the Mediterranean of our time,” insinuating that Western control was close to full. Similarly, the Mediterranean Sea has also been considered a NATO lake, not least through British sea power, the establishment of the U.S. Navy’s Sixth Fleet in 1946, and NATO’s southward expansion. NATO’s command of the sea was considered a given until the 1960s, when Soviet warships started to show up in numbers.1
A country or an alliance may field formidable naval forces, but control of the sea is conceptually and strategically different. The sea, unlike the land, cannot be fully controlled. Command of the sea is temporary and transient at best. It must be contextualized in sound military strategy and naval doctrine. Countries use naval forces to project their military power outward (to deter their enemies, for example, or launch an amphibious assault), and they retain forces to defend their coasts.
Armies, on the other hand, can control territory: roads, ports, railways, settlements, and significant swaths of an entire physical space. Projecting such use of military power—and, ultimately, political influence—to the sea leads to misconstrued perceptions of how that control should be obtained, used, and relinquished. The sea’s characteristics make it even more difficult; the maritime domain is truly multidimensional. It encompasses the undersea and seabed domains, the surface, the air, space, cyberspace, and the electromagnetic spectrum. All of these dimensions interact with one another, making the sea difficult to master.
This complexity forms a particular naval and maritime strategic culture that is unique to seafaring nations and their militaries. “To rule the waves,” as the British hymn has it, requires much more than a simple statement of intent or being a member of an alliance. Such a lofty goal encompasses vital aspects such as a defense-industrial and -intellectual base, strategy, natural and financial resources, and more. As three eminent navalists memorably put it, controlling the sea takes “men and women, machinery, management, manufacturing, money, and mentality.”2
The Political Geography of the Baltic Sea
It is true that most Baltic Sea coastal states have either joined NATO or are in the process of doing so. Denmark was a founding member of NATO in 1949. Germany (then West Germany) joined in 1955. Poland, a former member of the Warsaw Pact, joined in 1999. And Estonia, Latvia, and Lithuania joined in 2004, as former members of the Warsaw Pact and erstwhile republics of the Soviet Union. NATO’s Partnership for Peace program, beginning in 1994, institutionalized political-military relations with Finland, Sweden, and even Russia.
There have been times where the Baltic Sea looked, indeed, like a “flooded meadow.” This characterization originated tactically with the relative shallowness of the Baltic waters. But the term aptly fits a political and strategic setting where, at least for a while, cooperation and military trust building had replaced Cold War antagonism.
Since 2014, and especially since Russia’s invasion of Ukraine in 2022, the strategic realities have turned. Finland and Sweden have given up their long-standing policy of nonalignment to military alliances and submitted a joint request to join NATO. Helsinki officially joined on April 4, 2023, and Stockholm will soon be formally admitted.
At the same time, NATO-Russia relations have soured and have been virtually terminated since 2022. Russia’s formalized cooperation with NATO appears out of question for the foreseeable future, as there is no appetite on either side to engage in track 1 diplomacy. In other words, political antagonism will again define the Baltic Sea for some time to come.
Maritime Geography and the Correlation of Forces
Russia’s maritime geography has turned disadvantageous since 1991. The Cold War–era Soviet and Warsaw Pact coast, from which the Soviets staged their power projection against NATO, has been reduced to small pieces of Russian real estate in the St. Petersburg region of the Eastern Gulf of Finland and the Kaliningrad exclave. Like Russia’s post-Soviet army and air force, its navy suffered similar financial and intellectual underinvestment after the end of the Cold War. Its huge Cold War fleet of capital ships, boats, aircraft, and submarines fell into disrepair. Russia’s naval ambitions were curtailed.
The Russian Navy has since suffered catastrophes like the loss of the nuclear submarine Kursk in August 2000 in a naval disaster. Russia’s lone, aging, smoke-bellowing aircraft carrier, the Admiral Kuznetsov, has often been the subject of Western ridicule. The iconic Slava-class cruiser Moskva was sunk in the Black Sea in 2022 during hostilities with Ukraine. In the wake of such disasters, Russian President Vladimir Putin’s naval strategists have embraced Russia’s revision of post–Cold War developments by investing in undersea warfare capabilities (in no small part to avoid another humiliation like the Kursk), antiship and land-attack cruise and ballistic missiles, and the evolution of hybrid and information warfare.
Likewise, Western navies in the Baltic Sea now need to shift their attention back to the region after two and a half decades of post–Cold War reorientation. Denmark and Germany, whose navies had long been equipped to operate in the Baltic Sea, have transformed their navies (while shrinking them substantively) from national and alliance defense forces to expeditionary forces. They often provided maritime security in places such as the Horn of Africa, the Gulf of Guinea, and the Mediterranean Sea. Poland, more continentally minded than its neighbor across the Oder River, retained a small coastal navy and has been attempting to modernize and expand its forces for a number of years. Estonia, Latvia, and Lithuania have very small coastal navies; the main threat to their security was and remains a land-borne invasion from their east. It took some time to transform their militaries to NATO standards. Sweden and Finland retained national defense navies including coastal patrol crafts and amphibious forces. Their maritime forces need to be modernized and equipped for the new situation in the Baltic Sea, as well as contingencies on the whole northern flank and in other maritime theaters.
A serious problem is the alignment of threat perspectives. The view of the Baltic Sea from Germany is principally maritime in nature—to include naval forces in support, but also significant land and air forces as demonstrated by the forward-positioned brigade in Lithuania or the Luftwaffe’s frequent support of NATO’s Baltic Air Policing missions. Sweden and Finland, with their sizeable rugged coastlines, are giving coastal defense (such as amphibious raids) a higher priority, with modern air forces completing the efforts. The three Baltic states, which do not possess air forces and field only very small navies, must rely on other measures to think about the next war: allies and their forward-positioned ‘tripwire forces’, societal resilience, stay-behind forces, counter-cyber capabilities, and other nontraditional means.
NATO allies in the Baltic Sea region have the significant task to formulate and coordinate a coherent defense posture. In the era of jointness, that means the proper force mix of military, diplomatic, and economic measures to deter Russian adventurism and, should that fail, robust warfighting capabilities. All of this would have to happen with significantly less warning time than previous governments around the Mare Balticum were led to believe.
Legal and Naval Considerations
The Baltic Sea is an enclosed body of water, but under the 1994 United Nations Convention on the Law of the Sea (UNCLOS), it is in effect an open sea where littoral and non-littoral states can trade, operate navies, and more. Compared to the Black Sea, whose access is constrained under the terms of the 1936 Montreux Convention, the limits to naval activity in the Baltic Sea are purely operational. This includes the fact that its confined and shallow brackish waters make operations with larger aircraft carriers or nuclear attack submarines unfeasible.
As a vital area of coastal and international trade and tourism, the Baltic Sea is open to seafaring nations. The Kiel Canal, which connects the Baltic Sea with the North Sea, is the busiest artificial waterway in the world. It sees cargo and passenger ships with flags from all over the globe, including Indian-flagged tankers carrying Russian oil (thereby undermining Western sanctions). Routine deployments of warships and their respective partners make the area a naval hotspot: the U.S. Navy, the British Royal Navy, the Spanish Armada (all NATO member states), the Chinese People’s Liberation Army Navy, the Pakistan Navy, and the Indian Navy all plow these waves for a variety of naval and strategic intents.
It should be no surprise that Russia will continue to use the Baltic Sea and NATO’s northern flank for its own commercial, military, and strategic purposes for the foreseeable future. It will likely stage exercises together with China, which is fully in line with international law and quite common. NATO members that wish to underline the rule of law in international relations, not least with an eye toward the South China Sea, should become comfortable with these exercises. But Russia will likely harass NATO member states’ traffic when and where Moscow finds an advantage, as well as threaten commercial cargo, energy, and data traffic by hybrid means. These tactics are threats to maritime safety and security in the region; they are unacceptable and must be deterred.
NATO member states should not fall prey to the idea that closing off the Baltic Sea would help maintain maritime security and deter Russian adventurism. Instead, the Baltic Sea must continue to be international waters and the site of important multilateral naval exercises, such as Baltic Operations (BALTOPS) and Northern Coasts (NoCo). A cordoned-off Baltic Sea—even if just for commercial cargo, as suggested by Latvian President Edgars Rinkēvičs in October 2023—would create a dangerous precedent for other seas. NATO and its partners have been cautious to support the rule of law and the freedom of the seas in line with UNCLOS and the Montreux Convention. Hence, they need to be very conscious of the implications of unilateral actions in the Baltic Sea.
The United States has a history of acting as a guardian of the maritime system. In the mid-1980s, U.S. Navy warships entered the Black Sea repeatedly to test the Soviet Navy’s response. Reckless Soviet responses yielded collisions and shouldering incidents. In North Africa, Libyan dictator Muammar Gaddafi unilaterally expanded his country’s coastal waters into the Gulf of Sidra, where he met a mighty naval force buttressed by the then-overwhelming U.S. Sixth Fleet stationed in Naples, Italy. This resulted in brief and bloody wars against Gaddafi. The U.S. Navy and its allies also made sure the Baltic Sea remained an operating area during the Cold War. In 1985 (and once more in 1989), the reactivated battleship USS Iowa (BB-61) entered the Baltic Sea as a show of force—although its accompanying Ticonderoga-class guided missile cruiser, fitted with the new Aegis defense system, likely gave the Soviets the larger headache. The USS Iowa conducted live-firing exercises in the central Baltic Sea, putting a hole in the Soviet and East German attempts just a decade earlier to declare the sea a closed body of water. Their thinly veiled Sea of Peace initiative would have prevented non-littoral states from deploying warships in the Baltic Sea, effectively giving the Warsaw Pact full control over it for its military operations.
Undermining the maritime order in one region does more harm than good, for the consequences can be wide-ranging or even global. For this very reason, the United States and its allies conduct freedom of navigation exercises in the South China Sea and the Taiwan Strait. These exercises remind China and others of the universality of international norms (the U.S. abstention from ratifying UNCLOS notwithstanding).
Charting the Course: The NATO Lake You Are Looking For
NATO in the Baltic Sea is faced with a dilemma familiar to a number of European navies—namely, how to grow the size of its fleet and remain balanced at the same time. How much should be invested in high-end capabilities? In the European context, that means answering the key question of just how high intensity their planning for naval operations should proceed. The United States, with its commanding defense-industrial base and an articulated “warfighting first” attitude, is an ally with whom to interoperate at sea. Politically, the United States is also a market to purchase material from, and its defense companies remain a powerful agent of defense change. At the same time, strategically, there continue to be doubts about American steadfastness, particularly after the upcoming 2024 U.S. election. (Congressional support of Ukraine is widely seen as an indicator of Baltic Sea support should the Republicans win the White House and/or the Senate in 2024.)
Besides issuing a highly desirable comprehensive Alliance Maritime Strategy (updating its 2011 version) or dusting off its 1980s Concept of Maritime Operations (CONMAROPS), NATO would be well advised to use the emerging political focus on its seas to its advantage. If it must, the alliance could spin the “NATO lake” moniker to its advantage. It should underline that NATO naval operations in the Baltic Sea are meant to safeguard cargo and energy transfers, as well as provide maritime security for the international community. NATO member states with larger navies have acted precisely as such benevolent maritime guardians in the Baltic Sea and elsewhere before the 2014 watershed moment. At the same time, the alliance could use its properly equipped naval forces (including ships, aircraft, and uncrewed platforms) to deter Russia and its partners from adventurism in the Baltic Sea. Displaying the broad spectrum of its naval forces and realizing NATO’s inherent maritime mindset would be useful to position the alliance for future challenges in northern Europe.
NATO should return to its maritime roots, recalling what the “A” stands for. It could use the Baltic Sea as a model region for other maritime theaters, ensuring freedom of navigation for all benevolent users of the sea. With the help of the capable defense and shipping industry in the Baltic Sea, the alliance could bring sea power into the twenty-first century. The alliance needs to make sure—through efforts in both the public domain and by not over-regionalizing the Baltic Sea through atomized command structures—that the seas remain free, open, and interconnected. What happens in the Baltic does not necessarily stay in the Baltic.
The characterization of the Baltic Sea as a NATO lake raises the most ire with those who for many years have studied the region, as well as those who study maritime security, naval strategy, and sea power. There is much opportunity in decreasing NATO’s seablindness, but it needs to be wielded carefully.
Notes
1 Peter Swartz, “Preventing the Bear’s Last Swim: The NATO Concept of Maritime Operations (CONMAROPS) of the Last Cold War Decade,” in NATO’s Maritime Power 1949-1990, ed. I. Loucas and G. Marcoyannis (Keffalonia, Greece: Inmer Publications, 2003), 47–67.
2 David Rosenberg, Jon Sumida, and Winfried Stallmann, cited in Sebastian Bruns, US Naval Strategy and National Security: The Evolution of American Maritime Power (London: Routledge, 2018), 32.
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