NATO and the Protection of Undersea Cables: US Interests and Flow Security Interdependence

The protection of undersea cables represents a critical security challenge for the United States and its allies in an era of increasing great power competition. NATO provides a valuable framework for coordinating multinational responses to threats against this vital infrastructure, demonstrating the concept of flow security interdependence in practice. The Alliance's existing initiatives, including the Baltic Sentry operation and the Maritime Centre for Security of Critical Underwater Infrastructure, serve US interests by distributing the security burden while maintaining American leadership.
 
However, significant limitations constrain NATO's effectiveness in this domain. Legal and jurisdictional challenges in international waters, divergent interests among member states, and the predominantly private ownership of cable infrastructure all complicate the Alliance's protective role. A comprehensive approach to undersea cable security will require combining NATO's military capabilities with broader international legal frameworks, public-private partnerships, and competitive market strategies.
 
As international security experts warn about an emerging era of undersea conflict, galvanizing international action through NATO represents an important component of protecting what has been aptly described as the "soft underbelly of American power." However, this approach must be part of a broader, multi-faceted strategy that addresses the full spectrum of vulnerabilities facing this critical global infrastructure.

NATO and the Protection of Undersea Cables: US Interests and Flow Security Interdependence 
Recent incidents involving subsea cable damage have highlighted the vulnerability of critical underwater infrastructure that underpins global communications, finance, and security. In November 2024, two submarine telecommunication cables (BCS East-West Interlink and C-Lion1) were disrupted in the Baltic Sea[2]. These incidents followed earlier damage to subsea cables in the Baltic region and the severing of three undersea cables in the Red Sea in February 2024[3][10]. Most recently, Taiwan detained a Chinese-crewed ship after a subsea cable was cut near the island in February 2025[4]. As these incidents proliferate, there is growing recognition that undersea infrastructure represents a critical vulnerability in global security architecture. This report examines the extent to which NATO provides a viable framework for protecting undersea cables, particularly from the perspective of US interests, while also considering limitations and alternative approaches.
 
 The Strategic Significance of Undersea Cable Networks to US Interests
 
 Economic and Technological Imperatives
 
The United States has profound economic interests in ensuring the integrity of the global undersea cable network. American technology giants like Google and Meta (mentioned in the query) have become significant investors in and owners of these cables, making them crucial assets for US technological dominance. These companies rely on the uninterrupted flow of data across continents to maintain their global services and competitive edge.
 
More broadly, the financial sector—a cornerstone of American economic power—depends heavily on these cables. An estimated $10 trillion in financial transactions traverse these networks daily[8][13]. Any significant disruption would have immediate and severe consequences for US financial markets and the broader economy. A major international bank moves approximately $3.9 trillion through these cable systems every workday[17]. This economic vulnerability cannot be overstated.
 
 Military and National Security Dimensions
 
The US military's dependence on undersea cables represents another crucial dimension of American interest. Despite having dedicated military communication systems, the vast majority of the Department of Defense's command-and-control information flows through commercial undersea cables[5]. This reliance creates a significant vulnerability that potential adversaries could exploit during conflicts.
 
Historical precedents demonstrate the strategic significance of undersea cables during wartime. The United States cut Spain's undersea cables during the Spanish-American War of 1898, while Britain severed German cables at the outset of both World Wars[5]. These historical examples underscore that targeting communications infrastructure has long been a component of military strategy, and today's digital-dependent military operations are even more vulnerable to such disruptions.
 
 Geopolitical Competition
 
The undersea cable network has become an arena for great power competition. Russia and China are actively developing means to interfere with these cables as part of their hybrid warfare capabilities[5][11]. The Atlantic Council's assessment indicates that Russia maintains the technical capability to target critical undersea infrastructure to damage Western digital networks[11]. Similarly, China's Digital Silk Road initiative has expanded its access to and influence over submarine cables, raising concerns about potential strategic manipulation[7].
 
 NATO's Role in Protecting Undersea Infrastructure
 
 Current NATO Initiatives
 
In response to the escalating threat to undersea infrastructure, NATO has implemented several initiatives that directly serve US interests. In January 2025, NATO launched the "Baltic Sentry" operation specifically designed to protect undersea cables in the Baltic Sea region[8][14]. This mission involves deploying naval assets, including frigates, maritime patrol aircraft, and naval drones, to enhance surveillance and deterrence against potential threats to underwater infrastructure[8].
 
NATO Secretary General Mark Rutte emphasized the gravity of these threats when announcing the Baltic Sentry mission, noting that more than 95% of internet traffic is secured via undersea cables, with 1.3 million kilometers of cables guaranteeing an estimated $10 trillion worth of financial transactions daily[8]. This recognition at NATO's highest levels demonstrates the Alliance's understanding of the strategic importance of these assets.
 
Additionally, NATO has established a Maritime Centre for Security of Critical Underwater Infrastructure to coordinate the protection efforts[12]. This indicates the Alliance's institutional commitment to addressing this emerging security challenge.
 
 Flow Security Interdependence Through NATO
 
The concept of "flow security interdependence" is particularly relevant to understanding why NATO provides an effective framework for protecting undersea cables. This approach recognizes that the security of critical flows—whether data, energy, or goods—requires collective action because disruptions affect multiple nations simultaneously.
 
NATO's collective defense principle, embodied in Article 5, provides a powerful deterrent against deliberate attacks on undersea infrastructure. By framing cable protection as a collective security issue, NATO can leverage its combined military capabilities and intelligence resources to monitor, deter, and respond to threats. This multilateral approach aligns with US interests by distributing the burden of security while maintaining American leadership within the Alliance.
 
The US-led coordination with Nordic-Baltic allies on undersea cable security demonstrates this approach in action. In January 2025, Anne Neuberger, the US Deputy National Security Advisor for Cyber and Emerging Technology, engaged in discussions with counterparts from Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, Norway, and Sweden to strengthen cooperation on protecting vital undersea cables[1]. This form of multilateral engagement through NATO amplifies US influence while sharing the operational and financial burden of security provision.
 
 Devil's Advocate: Limitations of the NATO-Centered Approach
 
 Legal and Jurisdictional Challenges
 
Despite NATO's capabilities, significant legal and jurisdictional obstacles complicate the protection of undersea cables. The majority of these cables traverse international waters, where regulatory frameworks are limited and enforcement mechanisms are weak[12][13]. As Captain Niels Markussen, director at NATO's Maritime Centre for Security of Critical Underwater Infrastructure, noted: "If you go outside territorial waters, in principle there's not much regulation – this makes the area attractive for those who want to operate outside the jurisdiction"[12].
 
The UN Convention on the Law of the Sea (UNCLOS) differentiates between territorial waters, international waters, and Exclusive Economic Zones, but specific responsibilities for security remain vague for the vast sections of undersea infrastructure intersecting international waters or multiple countries' EEZs[13]. These legal gaps cannot be fully addressed by NATO alone and would require broader international legal frameworks.
 
 Divergent Interests Within NATO
 
NATO's effectiveness in protecting undersea infrastructure is limited by divergent interests among member states. Turkey's hesitation to fully commit to collective defense measures in the Black Sea exemplifies this challenge[6]. Despite Romania's vocal support for increased NATO presence in the region, Turkey's "middleman" approach to relations between Russia and the West has hindered progress toward sufficient maritime defense[6].
 
These divergent interests could similarly affect NATO's response to undersea cable threats in other regions. The US might find that its priorities for cable protection do not align perfectly with those of other NATO members, potentially limiting the effectiveness of collective action.
 
 Private Ownership Complicates Response
 
A significant challenge to NATO's protective role stems from the predominantly private ownership of undersea cables. Many of these cables are owned by international consortia of private telecommunication companies[16][17], creating a complex landscape of stakeholders with varying priorities and interests.
 
This private ownership model creates potential gaps in security coordination. While NATO can provide military protection, it has limited authority over the design, routing, maintenance, and repair decisions made by private companies. The public-private coordination necessary for comprehensive security remains underdeveloped, potentially limiting NATO's effectiveness despite its military capabilities.
 
 Alternative Approaches to Protection
 
While NATO represents one important framework for protecting undersea cables, alternative or complementary approaches deserve consideration. The "competitive response" approach advocates for US competition with China in the submarine cable market through alternate assistance programs, which would increase the redundancy of secure networks[7]. This market-based approach might be more flexible than the NATO military framework in some contexts.
 
A combination of strategies might prove most effective. A 2021 study outlined four potential US policy responses to Chinese threats to submarine cables: isolationist (disconnecting from insecure networks), cooperative (emphasizing international norms), competitive (competing in the submarine cable market), and militaristic (using military assets to defend cables)[7]. The most robust approach likely combines elements of all these strategies rather than relying solely on NATO's military capabilities.
 
 Future Prospects for US-NATO Collaboration on Undersea Security
 
 Strengthening NATO's Maritime Domain Awareness
 
To maximize NATO's utility for US interests in cable protection, enhanced maritime domain awareness capabilities should be prioritized. The increased deployment of surveillance assets through operations like Baltic Sentry represents a positive step, but more comprehensive monitoring systems are needed, particularly in vulnerable chokepoints where multiple cables converge.
 
NATO's experience with counterpiracy operations and maritime security provides a valuable foundation for expanding into undersea infrastructure protection. Building on these capabilities while incorporating new technologies for underwater surveillance would strengthen the Alliance's protective capacity.
 
 Developing Clearer Legal Frameworks
 
The US can lead efforts within NATO to develop clearer legal frameworks for responding to attacks on undersea infrastructure. While full international consensus may be difficult to achieve, NATO could establish internal protocols and response mechanisms that provide greater clarity for operations in international waters.
 
The New York Joint Statement on the Security and Resilience of Undersea Cables, proposed by the United States and endorsed by several allies in September 2024, represents an important step toward establishing principles for cable security[15]. Building on this foundation through NATO channels could help address some of the jurisdictional challenges identified earlier.
 
 Conclusion
 
The protection of undersea cables represents a critical security challenge for the United States and its allies in an era of increasing great power competition. NATO provides a valuable framework for coordinating multinational responses to threats against this vital infrastructure, demonstrating the concept of flow security interdependence in practice. The Alliance's existing initiatives, including the Baltic Sentry operation and the Maritime Centre for Security of Critical Underwater Infrastructure, serve US interests by distributing the security burden while maintaining American leadership.
 
However, significant limitations constrain NATO's effectiveness in this domain. Legal and jurisdictional challenges in international waters, divergent interests among member states, and the predominantly private ownership of cable infrastructure all complicate the Alliance's protective role. A comprehensive approach to undersea cable security will require combining NATO's military capabilities with broader international legal frameworks, public-private partnerships, and competitive market strategies.
 
As international security experts warn about an emerging era of undersea conflict, galvanizing international action through NATO represents an important component of protecting what has been aptly described as the "soft underbelly of American power." However, this approach must be part of a broader, multi-faceted strategy that addresses the full spectrum of vulnerabilities facing this critical global infrastructure.
 
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