How Undersea Cables Became the Internet's Hidden Power Struggle

The internet is not the cloud. It is not satellites or wireless signals. It is, as then-Senator Ted Stevens put it in 2006, a "series of tubes," and most of those tubes run underwater. Subsea fiber-optic cables connect more than 100 coastal states and carry over 98% of all intercontinental internet and telecom traffic, according to Foreign Affairs. Without these cables, international transactions would simply stop. The pandemic proved this: when usage spiked, the cables held, but the margin was thinner than most people realized. Samanth Subramanian, author of The Web Beneath the Waves, has spent years tracing this infrastructure from Victorian telegraph roots to modern fiber optics. His work reveals a network that is both remarkably durable and alarmingly vulnerable, hidden beneath thousands of feet of water and largely ignored until something breaks.

Subramanian's fascination began with a 1990s essay by novelist Neal Stephenson, who documented cable-laying with obsessive detail. The subject resurfaced for Subramanian in 2022, when a volcanic eruption near Tonga severed the island nation's cable connection. Parts of the Pacific archipelago went without broadband for over 16 months. That single point of failure, and the isolation it caused, became the seed of his book. As he told The Hindu, most people scroll through reels or stream Netflix without considering the physical infrastructure making it possible. The cables are mundane until they are not.

The undersea cable business has undergone a quiet revolution in ownership. What began as consortia of national telecom companies has shifted dramatically toward technology companies building their own intercontinental infrastructure. Google and Meta now commission and operate private cable systems, giving them unprecedented control over global data flows. This shift matters because it concentrates power in unregulated corporate hands and changes how the internet is governed. National telecoms, for all their flaws, operated within regulatory frameworks and diplomatic agreements. Tech companies answer to shareholders and operate across jurisdictions with patchy oversight.

The economics drove this change. Tech companies generate the traffic, so they capture the value of owning the pipes. But the geopolitical implications are substantial. According to Foreign Affairs, this new ownership structure makes undersea networks attractive targets for state actors seeking disruption. China and Russia have both weaponized undersea infrastructure, either through surveillance or sabotage planning. The cables sit in international waters, protected by laws written for a different era. When a private American company's cable carries European banking data through the South China Sea, which nation's laws apply? Which navy protects it? These questions remain unanswered, and the stakes grow as more critical services migrate online.

The Tonga eruption was not an isolated case. Cables break constantly. Anchors drag through them, earthquakes shift the seabed, and fishing equipment snags them. Most breaks are repaired within days, but the Tonga case showed what happens when geography, politics, and bad luck align. The island was cut off from the world for over a year because replacement cable ships were scarce, spare parts were not stored regionally, and the depth of the break made repair exceptionally difficult. The internet felt like a local utility to Tongans until it vanished entirely.

Subramanian's work, discussed on Bloomberg's Odd Lots podcast, emphasizes that redundancy is the only real protection. Where multiple cables serve the same route, traffic reroutes automatically. But redundancy is unevenly distributed. Wealthy coastal regions have multiple overlapping systems. Island nations and developing economies often depend on single connections. The global internet looks resilient in aggregate but contains thousands of single points of failure. Climate change adds new risks: melting ice opens new routes but also destabilizes seabeds, and more intense storms challenge both cable burial and repair operations. The infrastructure was built for a stable ocean, and the ocean is changing.

The strategic importance of undersea cables has not escaped military and intelligence planners. Subramanian details how undersea infrastructure has become a focus of great-power competition. Russia operates specialized submarines capable of operating at cable depths. China has invested heavily in cable manufacturing and laying capacity, giving it influence over which nations connect to the global network and on what terms. The United States and its allies have responded with increased naval patrols and diplomatic pressure on cable landing permissions.

This competition creates dilemmas for smaller nations. Choosing a Chinese-built cable or a Chinese-approved route can bring investment and faster deployment. It can also expose a nation's communications to monitoring or disruption in a future conflict. The same logic applies to American or European systems. Neutrality is difficult when the infrastructure itself becomes a battlefield. Foreign Affairs notes that the shift from telecom consortiums to tech ownership has complicated this further: governments negotiate with corporations that have more market capitalization than many states and no historical loyalty to any particular flag. The cable network was designed for commerce, not warfare, but it now sits at the intersection of both.

The hidden physical layer of the internet is becoming harder to ignore. As Subramanian argues across his interviews and in The Web Beneath the Waves, the mythology of the internet as immaterial, weightless, and resilient has obscured real vulnerabilities that policy and investment have not kept pace with. The book and podcast arrive at a moment when awareness is catching up to reality: multiple cable breaks in the Red Sea in 2024 disrupted connectivity between Europe and Asia for weeks, and similar incidents in the Mediterranean have exposed how concentrated traffic remains on a handful of routes.

For ordinary users, the implication is that internet reliability should not be taken for granted. For policymakers, it is that critical infrastructure protection must extend below the waterline. For the technology industry, it is that vertical integration into physical infrastructure carries geopolitical responsibilities that quarterly earnings reports do not adequately capture. The internet's next chapter may be defined less by software innovation than by who controls, protects, and can sever the cables on the ocean floor. Subramanian's work makes that story accessible, which is perhaps its most valuable contribution. The tubes are not changing. But who owns them, who threatens them, and who can repair them when they break, increasingly defines what the internet actually is.