A former Taiwanese legislator warned a congressional commission Monday that China is deploying a shadow maritime network to systematically sever undersea internet cables, posing a severe and immediate threat to global semiconductor supply chains and Taiwan's national security.
Jason Hsu (許毓仁), now a senior fellow at the Hudson Institute, delivered the stark assessment during a hearing of the U.S.-China Economic and Security Review Commission. The March 2 hearing, titled "Part of Your World: U.S.-China Competition Under the Sea," was held at the Dirksen Senate Office Building and led by Commission Chair Randall Schriver and Vice Chair Michael Kuiken.
Testifying on a panel focused on undersea infrastructure alongside other experts, Hsu argued that the vulnerability of undersea cables is not a future risk, but a present and escalating crisis.
He described undersea cables as the barbed wire of the 21st-century digital order, separating stability from isolation.
According to Hsu's testimony, approximately 97% of global intercontinental data transmission relies on undersea fiber-optic cables. Taiwan is connected to the world by just 24 of these cables, which critically support its semiconductor manufacturing, financial markets, civilian communications, and military command systems.
Hsu estimated that a prolonged internet outage would inflict daily economic losses of $55 million on Taiwan alone, excluding the devastating chain reaction it would cause across the global semiconductor supply chain.
He pointed to a string of recent suspicious incidents to illustrate the growing hybrid warfare threat.
In February 2023, two cables connecting Taiwan to its outlying Matsu islands were severed within six days by a Chinese fishing boat and a cargo ship dragging its anchor, leaving 14,000 residents with crippled internet for over 50 days.
Between January and February 2025, Taiwan recorded four additional cable damage incidents. One involved a Tanzania-flagged, Hong Kong-controlled vessel with a Chinese crew that deliberately turned off its location transponder before dragging its anchor across a major trans-Pacific cable.
Another vessel, the Hong-Tai 58, operated under two different names and three different national registries before severing a cable between Taiwan and Penghu.
Hsu also highlighted growing Sino-Russian coordination, citing the November 2024 incident in the Baltic Sea where the Chinese vessel Yi-Peng 3, carrying Russian crew members, severed two European cables after dragging its anchor for over 100 miles.
In Chinese military doctrine, cutting undersea cables is a priority for the early stages of a conflict, Hsu noted. By targeting just three key cable groups near the Bashi Channel, China could theoretically eliminate 95% of Taiwan's international bandwidth. Combined with cyberattacks and satellite jamming, this would form a multi-domain strategy to blind the island.
While satellite communications are vital for resilience, Hsu warned they lack the capacity to replace fiber-optic cables and can only buy time during a crisis. Compounding the danger, cables take an average of 40 days to repair in peacetime. Taiwan currently possesses no domestic cable repair ships, making wartime restoration nearly impossible.
To counter the threat, Hsu offered a series of policy recommendations for both Washington and Taipei. He urged the U.S. Congress to pass a "Taiwan Undersea Resilience Initiative Act," update international cable protection laws that date back to 1884, and strictly enforce sanctions against proxy sabotage vessels.
For Taiwan, Hsu recommended building an indigenous cable repair fleet—potentially in cooperation with Japan—enhancing Coast Guard patrols over critical cable routes, and decentralizing cable landing stations to eliminate geographical bottlenecks. （Related： Taiwan's Inadequate Response to Iran Crisis Exposes Flawed Priorities ｜ Latest ）
Hsu concluded his testimony with a pointed message aimed directly at his former colleagues in Taipei, urging the Legislative Yuan to swiftly pass a stalled national defense budget.
