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In the popular imagination, the internet is a “cloud”—an ethereal, wireless network that transmits data through the air. This metaphor masks the physical reality of the global digital economy. The internet is not wireless. It is deeply, vulnerably physical.
Approximately 1.4 million kilometers of fiber-optic cable lie on the ocean floor, traversing the world’s deepest trenches and most contentious maritime chokepoints. These cables, often no thicker than a garden hose, are the central nervous system of modern civilization, carrying between 95 and 99 percent of all intercontinental data traffic.
For the United States, the security of this subsea network has evolved from a telecommunications policy matter into a tier-one national security priority. The cables don’t merely carry Netflix streams and social media feeds. They transport the operational data of the U.S. military, the diplomatic cables of the State Department, and the SWIFT transactions that underpin the global financial system.
As the digital economy expands into cloud computing, artificial intelligence, and the Internet of Things, the reliance on these physical tubes of glass has become absolute. Satellites, often cited as a backup, lack the bandwidth and latency capabilities to serve as a viable alternative for the massive throughput required by the modern world.
The vulnerability of this infrastructure is stark. Historically, threats were primarily accidental—fishing trawlers and natural disasters. Today, however, the seabed has become a domain of strategic competition. From “gray zone” sabotage in the Baltic Sea to the diplomatic tussle over cable ownership in the Indo-Pacific, the United States is engaged in a complex, multi-front effort to secure the physical layer of the internet.
The Physical Internet
To understand the U.S. security strategy, you first need to grasp the physical and economic magnitude of the asset being protected. The global subsea cable network acts as the backbone of the internet, a sprawling web of approximately 600 systems that connect every continent except Antarctica.
Subsea Fiber Dominates
The misconception that satellites carry the bulk of global traffic persists, yet it’s factually incorrect. Satellites account for less than 1 percent of transoceanic data traffic. The remaining 99 percent travels via subsea cables.
The physics of light transmission through fiber-optic glass allows for bandwidth capacities that satellites cannot match. Modern cables can transmit hundreds of terabits per second, a necessity for a world increasingly reliant on bandwidth-heavy applications.
The surge in demand for data centers, driven by the explosive growth of Large Language Models and generative AI, has further intensified this dependency. These technologies require massive datasets to be moved between continents for training and inference, creating a feedback loop where digital innovation necessitates physical infrastructure expansion.
The cables are no longer just dumb pipes. They are strategic assets that define which nations hold the keys to the future digital economy.
Economic Stakes
The economic implications of a major cable disruption are catastrophic. The network facilitates trillions of dollars in daily financial transactions. One major international bank alone is estimated to move $3.9 trillion through these systems every workday.
A severed connection doesn’t just result in slow internet speeds. It can halt stock trades, freeze international supply chains, and isolate entire economies.
This dependency creates a “single point of failure” risk profile. For many developing nations, and even some U.S. territories like Guam or Hawaii, connectivity hangs by a thread—or rather, a few strands of fiber. If those strands are severed, the digital blackout is total.
The 2022 volcanic eruption in Tonga, which severed the nation’s only cable and isolated it for weeks, served as a grim preview of what a targeted attack could achieve.
Vulnerability
Despite their critical importance, subsea cables are surprisingly fragile. They are laid directly on the seabed, exposed to the harsh marine environment.
In waters shallower than 1,500 meters, cables are typically buried under the seabed using sea plows to protect them from fishing gear and anchors. However, burial is not always possible due to seabed geology.
In the deep ocean, cables rest directly on the floor. While they are safe from fishing nets here, they are vulnerable to underwater landslides and, increasingly, sophisticated sabotage capabilities.
The point where a cable rises from the sea and connects to the terrestrial grid is known as a cable landing station (CLS). These facilities are critical chokepoints. A single CLS may house the termination points for multiple intercontinental cables, meaning that a physical attack or power outage at one building could disrupt connectivity for an entire region.
The Threats
The U.S. government’s approach to cable security is driven by a recognition that the threat landscape has shifted fundamentally. For decades, the primary enemy of the subsea cable was the fishing trawler. Today, it is the state actor operating in the “gray zone.”
Accidents and Nature
Historically, roughly 70 percent of all cable faults are caused by human activity, primarily fishing and anchoring. Trawlers dragging heavy nets along the bottom can snag a cable, snapping it or damaging its insulation. Similarly, ships dropping anchor in designated cable protection zones—often due to negligence or mechanical failure—are a frequent cause of disruption.
Natural disasters remain a potent threat. Earthquakes can trigger submarine landslides that sever multiple cables simultaneously, as seen in the 2006 Hengchun earthquake off Taiwan. Climate change is also introducing new variables; rising sea levels and more intense storms threaten the physical integrity of coastal landing stations.
Espionage
The potential for subsea cables to be used for espionage has been a concern since the Cold War. Modern fears focus on two primary mechanisms.
Sophisticated adversaries may attempt to install physical taps on the cable itself to copy data streams. This requires specialized submersibles and is technically difficult but possible for advanced navies.
A more insidious threat lies in the equipment used to operate the cable. If the “wet plant” (the cable and repeaters on the ocean floor) or the “dry plant” (the transmission equipment in the landing station) is manufactured by an untrusted vendor, they could theoretically insert “backdoors” allowing for remote data exfiltration or a “kill switch” to disable the system.
The U.S. government has publicly raised concerns that Chinese companies, specifically Huawei Marine Networks (now HMN Tech), could be compelled by Chinese intelligence laws to facilitate such espionage.
Gray Zone Sabotage
The most alarming development is the rise of deliberate sabotage disguised as accidents—a tactic known as “gray zone” warfare. This involves the use of commercial vessels, such as fishing boats or cargo ships, to damage infrastructure in a way that allows the perpetrator to deny responsibility.
In February 2023, the two cables connecting Taiwan to its outlying Matsu Islands were severed within six days of each other. The first was cut by a Chinese fishing vessel, the second by a Chinese cargo ship. The incident left 14,000 residents with severely degraded connectivity for weeks.
While Beijing claimed these were accidents, the timing and frequency (27 breaks in five years) suggest a calculated campaign of harassment and testing of Taiwanese resilience.
Europe has witnessed a spate of suspicious cable severing. In late 2024, the C-Lion1 cable between Finland and Germany and the BCS East-West Interlink between Sweden and Lithuania were cut. Investigations centered on the Yi Peng 3, a Chinese-owned bulk carrier that was observed dragging its anchor through the area.
These incidents have highlighted the difficulty of attributing blame and responding to acts that fall below the threshold of open war.
Advanced Naval Capabilities
Beyond gray zone tactics, the U.S. is deeply concerned about the specialized naval capabilities of the Russian Federation. The Main Directorate of Deep-Sea Research (GUGI) operates a fleet of spy ships and submarines designed specifically for seabed warfare.
The Yantar, a Russian oceanographic research vessel, has been frequently tracked loitering near critical cable routes. It carries autonomous underwater vehicles and manned submersibles capable of descending to great depths to cut or tap cables.
The Losharik, a nuclear-powered deep-diving submarine, is capable of manipulating objects on the seafloor.
The existence of these assets forces the U.S. and NATO to treat cable protection not just as a law enforcement issue, but as a theater of anti-submarine warfare.
The Evolving Threat Matrix
| Threat Category | Primary Agent | Mechanism of Action | U.S. Counter-Strategy |
|---|---|---|---|
| Accidental | Fishing / Shipping | Trawling nets, anchors dragging | NOAA charting, USCG patrols, industry education |
| Natural | Environment | Earthquakes, landslides, climate | Route diversity, hardening landing stations (CISA) |
| Espionage | State Actors | Taps, network management software backdoors | Team Telecom review, vendor exclusion (FCC) |
| Gray Zone | State-linked Civilian | “Accidental” anchor drops by militia vessels | AIS monitoring, diplomatic pressure, repair redundancy |
| Hard Military | Specialized Navy | Deep-sea submersibles cutting/tapping | Naval surveillance, ASW operations, sensor integration |
The Regulatory Defense
The first line of defense in the U.S. strategy is not a warship, but a lawyer. The United States government utilizes a robust regulatory framework to control market access, ensuring that cables landing on U.S. soil are owned, operated, and supplied by trusted entities.
Team Telecom
The primary mechanism for this oversight is the “Committee for the Assessment of Foreign Participation in the United States Telecommunications Services Sector,” informally known as Team Telecom. While it operated for years as an ad hoc group, it was formalized by Executive Order in 2020.
Team Telecom acts as an advisor to the Federal Communications Commission (FCC). Under the Cable Landing License Act of 1921, any company wishing to land a submarine cable in the U.S. must obtain a license. If that applicant has foreign ownership (typically a 10% threshold), the FCC refers the application to Team Telecom for a national security review.
The Committee is chaired by the Attorney General and includes the Secretary of Homeland Security and the Secretary of Defense. The Committee has the power to review specific questions about the applicant’s structure and can recommend that the FCC deny a license or revoke an existing one if the security risks cannot be mitigated.
The Review Process
To standardize the vetting process, the FCC and Team Telecom have developed a rigorous set of “Standard Questions” that applicants must answer. These questionnaires are comprehensive and intrusive, designed to flush out any hidden leverage a foreign state might have over the applicant.
Applicants must list every individual or entity with an equity interest. They must disclose any relationships, formal or informal, with foreign governments.
A critical technical vulnerability is “remote access”—the ability of an administrator to log into the cable’s network management system from another country. The Standard Questions explicitly ask if third-party vendors or owners will have remote access to the network for managed services.
Applicants must list the precise locations of their Network Operations Centers, data centers, and landing stations. They must also disclose all equipment vendors.
Mitigation and Exclusion
If Team Telecom identifies a risk—for example, a minority investor from a country of concern—it may negotiate a “Letter of Assurance” or a “National Security Agreement.” These are binding contracts where the operator agrees to specific security conditions, such as restricting access to the Network Operations Center to U.S. citizens with security clearances, housing all domestic data servers within the continental United States, and agreeing to annual security audits by U.S. government agencies.
However, for high-risk vendors, mitigation is no longer considered sufficient. The U.S. policy has shifted toward total exclusion, often referred to under the umbrella of the “Clean Network” initiative.
The FCC has proposed and implemented rules to ban the use of equipment from companies deemed “foreign adversaries,” specifically Huawei and ZTE, in U.S.-connected cables. The logic is that no amount of mitigation can safeguard a system if the underlying hardware is compromised.
This policy has led to the blocking of major projects. The Pacific Light Cable Network, originally backed by Google and Facebook (Meta) to connect Los Angeles to Hong Kong, was blocked by U.S. regulators due to the involvement of a Chinese partner, Dr. Peng Telecom & Media Group. The cable was eventually reconfigured to terminate in Taiwan and the Philippines, bypassing Hong Kong entirely.
This regulatory activism effectively forces the global industry to choose sides: if you want to connect to the United States (the world’s largest data hub), you cannot use Chinese equipment.
Homeland Security
While Team Telecom guards the front door, the Department of Homeland Security (DHS) and the Cybersecurity and Infrastructure Security Agency (CISA) work to ensure the resilience of the infrastructure that is already in place.
The U.S. government doesn’t own these cables—private companies do. Therefore, security must be a collaborative endeavor.
Supply Chain Resilience
In December 2024, DHS released a pivotal white paper titled “Priorities for DHS Engagement on Subsea Cable Security & Resilience.” This document, produced by the Supply Chain Resilience Center, outlines the department’s strategy for securing the industry’s complex supply chain.
The center identified three critical workstreams to bridge the gap between government and industry.
The subsea cable industry is distinct from the telecom sector or the maritime sector, often falling through the cracks of traditional engagement bodies. DHS is working to integrate cable operators into Sector Coordinating Councils to facilitate better threat intelligence sharing.
Industry leaders have long complained that the U.S. permitting process is a labyrinth of federal, state, and local approvals that can take up to three years. This delay is a security risk. It retards the replacement of aging, vulnerable cables with modern, more secure systems. DHS has committed to a comprehensive assessment to streamline these timelines.
In the event of a catastrophic cable break, operators often don’t know which federal agency to contact. DHS is developing a unified “concept of operations” to clarify federal roles during an emergency, ensuring that repair permits can be expedited and military assets mobilized if necessary.
Protecting Landing Sites
The vulnerability of subsea cables is not limited to the ocean floor. CISA has deployed its Regional Resiliency Assessment Program to evaluate cable landing stations.
CISA Region 2 (New York/New Jersey) is a global hub for transatlantic cables. CISA has conducted deep-dive assessments of the landing infrastructure, looking for vulnerabilities such as power redundancy, physical security, and climate resilience.
By identifying these gaps, CISA helps private operators prioritize their security investments.
Defense and Maritime Security
Regulatory oversight and resilience planning are vital, but they cannot stop a ship from dragging an anchor across a cable in the middle of the Pacific. For that, the United States relies on the “hard power” capabilities of the U.S. Navy and the U.S. Coast Guard.
Naval Seafloor Cable Protection Office
Buried within the Naval Facilities Engineering Command is the Naval Seafloor Cable Protection Office. Established in 2000, this office is the primary interface between the U.S. military and the commercial cable industry.
The office’s mission is rooted in the history of accidental damage. In the late 1990s, the Navy itself was responsible for an average of 10 cable breaks per year due to operational negligence (like anchoring in cable zones). The office was created to stop this fratricide.
Today, it manages the locations of all Navy and DoD cables and coordinates with commercial entities to ensure that military exercises don’t disrupt global communications. It serves as the “front office” for the DoD, representing military interests in policy discussions regarding seabed protection.
Cable Security Fleet
Perhaps the most critical operational vulnerability facing the U.S. is the shortage of cable repair ships. There are roughly 60 such vessels in the world, and very few are U.S.-flagged.
In the event of a conflict where cables are severed en masse, the U.S. would be dependent on foreign vessels to restore connectivity—vessels that might be unavailable or politically compromised.
To address this, the U.S. government created the Cable Security Fleet, modeled after the Maritime Security Program. The program pays a stipend (currently around $5 million per year per vessel) to private operators to keep their ships U.S.-flagged and crewed by American mariners. In exchange, these ships must be available to the Department of Defense during a national emergency.
As of 2024, the fleet consists of two ships, the CS Dependable and the CS Decisive, operated by SubCom.
Recognizing that two ships are insufficient, legislation such as the proposed “SHIPS for America Act” aims to increase the stipend to $12 million by 2034 and expand the fleet. This is driven by the reality that the Navy’s only dedicated cable ship, the USNS Zeus, is over 40 years old and nearing obsolescence.
Coast Guard Patrols
The U.S. Coast Guard has assumed a frontline role in monitoring the physical security of cables within the U.S. Exclusive Economic Zone. The Coast Guard monitors for “dark shipping”—vessels that turn off their Automatic Identification System transponders to hide their location. Dark vessels near cable routes are treated as high-priority targets for investigation.
Proposals have been made to formally designate the Coast Guard as the lead agency for subsea cable risk, granting it clearer statutory authority to interdict vessels suspected of sabotage.
NATO Operations
The U.S. doesn’t operate alone. In response to the Baltic Sea cuts, the U.S. supports NATO’s “Nordic Warden” operation. This initiative utilizes Artificial Intelligence to analyze maritime traffic data, flagging suspicious behavior by “shadow fleet” vessels (often Russian or Chinese merchant ships). When a risk is detected, the information is shared across the alliance, allowing for rapid interception by allied navies.
Economic Warfare
The U.S. strategy extends beyond defense into offense. The government is actively engaged in a global campaign to finance allied cable projects and displace Chinese infrastructure, specifically the “Digital Silk Road” initiative championed by Beijing.
The Chinese Challenge
The primary competitor in this space is HMN Technologies (formerly Huawei Marine). HMN Tech has historically won contracts by undercutting Western competitors by 20 to 30 percent, subsidized by state financing. The U.S. government argues that HMN Tech cables pose an unacceptable espionage risk and give Beijing coercive leverage over the host nations.
Financing Tools
To make Western alternatives competitive, the U.S. mobilizes its development finance arsenal.
The U.S. International Development Finance Corporation provides equity financing and loans to support infrastructure projects in the Indo-Pacific and beyond. This lowers the cost of capital for private consortia, allowing them to choose trusted vendors like SubCom (USA), NEC (Japan), or ASN (France) despite higher upfront costs.
The Export-Import Bank provides export credit insurance and loan guarantees to U.S. exporters. A flagship success for this approach was the Sea-Me-We 6 cable. This massive system connecting Singapore to France was initially poised to be awarded to HMN Tech.
Through a coordinated diplomatic and financial campaign, including nearly $4 million in training grants and EXIM financing support, the U.S. helped flip the contract to the U.S. firm SubCom. The $600 million project is now a secure link in the global network.
The Trilateral Partnership
The U.S. coordinates these efforts with its closest Pacific allies through the “Trilateral Partnership for Infrastructure Investment in the Indo-Pacific.” This bloc funds projects that are strategically vital but commercially unviable.
The East Micronesia Cable project to connect the island nations of Micronesia, Kiribati, and Nauru was originally tendered by the World Bank. When HMN Tech submitted the lowest bid, the U.S. and its allies intervened, fearing that a Chinese cable connecting to these strategic islands (and potentially the U.S. territory of Guam) was a security threat.
The allies nullified the original tender and agreed to fund the $95 million project themselves, awarding the contract to NEC.
The partnership financed a $30 million spur connecting Palau to a major trans-Pacific cable. This redundancy ensures that Palau remains securely connected to the U.S. digital sphere.
Future Challenges
As the U.S. solidifies its grip on the “Western” internet, analysts warn of a looming fracture—the “Splinternet.”
Digital Fragmentation
By aggressively banning Chinese vendors and blocking cables to Hong Kong, the U.S. is effectively creating a bifurcated internet: a U.S.-led trusted network and a China-led network.
While this enhances security for the U.S., it creates a risk of fragmentation where data cannot flow freely between the two spheres. This “digital iron curtain” could lock in friction and fragility, forcing third-party nations to choose sides in a zero-sum infrastructure game.
Legal Gaps
The United Nations Convention on the Law of the Sea provides weak protection for cables outside of territorial waters, treating damage largely as a civil matter. The U.S. is working to establish new norms, pushing for the criminalization of cable sabotage through bodies like the International Cable Protection Committee.
SMART Cables
Technologically, the U.S. is advocating for SMART Cables (Science Monitoring And Reliable Telecommunications). These cables integrate environmental sensors that can detect tsunamis and earthquakes.
Crucially, they also have dual-use potential for surveillance, capable of detecting acoustic signatures that could reveal the movement of submarines—a feature that aligns perfectly with the U.S. Navy’s desire for enhanced domain awareness.
Key U.S. Government Agencies and Their Roles
| Agency | Primary Role | Key Activities |
|---|---|---|
| Team Telecom (DOJ/DHS/DoD) | Gatekeeper | Reviews licenses, enforces mitigation agreements, blocks high-risk vendors |
| FCC | Regulator | Issues landing licenses, implements “Clean Network” bans on Huawei/ZTE |
| DHS (SCRC / CISA) | Resilience | Coordinates public-private intel sharing, assesses landing station security |
| U.S. Navy (NSCPO) | Defense | Coordinates fleet operations, represents DoD interests, monitors deep-sea threats |
| U.S. Coast Guard | Enforcement | Patrols EEZ, monitors “dark shipping,” investigates cable damage |
| State Department | Diplomacy | Negotiates international agreements, leads the “Trilateral Partnership” |
| DFC / EXIM Bank | Financing | Provides loans/grants to allied nations to buy trusted cable systems |
| MARAD | Logistics | Manages the Cable Security Fleet to ensure repair ship availability |
The U.S. strategy for securing subsea cables is a massive, complex undertaking that spans the depths of the ocean and the height of diplomatic negotiation. Through a combination of regulatory rigor, naval vigilance, and economic intervention, the United States is attempting to build a fortress around the invisible backbone of the world.
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