The US-China Economic and Security Review Commission held a hearing on Mar. 2 titled “Part of Your World: US-China Competition Under the Sea,” where former Taiwanese legislator Hsu Yu-jen (許毓仁) was invited to testify and stated that China is carrying out a deliberate and calibrated gray-zone campaign targeting Taiwan’s undersea cable infrastructure. He described it as one of the most urgent security threats facing the Indo-Pacific region.Hsu told the commission that “subsea cable security is not a future risk,” and “it is a present and accelerating danger.”Hsu mentioned that roughly 97% of global intercontinental data flows through subsea cables, and that disruptions to Taiwan’s 24 cable links could cripple its economy, disrupt global semiconductor supply chains, and cost an estimated $55 million per day. “The Taiwan Strait is not just a geopolitical fault line,” Hsu noted. “It is a data artery of the global economy.”Hsu cited a series of incidents since 2023, including repeated cable cuts near Matsu and other key corridors involving suspicious vessels, suggesting a coordinated shadow maritime network rather than isolated accidents. Under People’s Liberation Army doctrine, Hsu mentioned, severing undersea cables is considered an early step in a potential invasion. He added that targeting just three clusters near the Bashi Channel could reduce Taiwan’s international bandwidth by up to 90% to 95%. Combined with cyberattacks and satellite jamming, this could create a coordinated, multi-domain strategy to deny information from space to the seabed.Hsu urged Congress to pass the Taiwan Undersea Cable Resilience Initiative Act, modernize what he described as the outdated 1884 cable protection convention, and expand sanctions against vessels and proxy actors engaged in cable sabotage. He also said Taiwan must build indigenous repair capacity with Japan, diversify cable landing stations, and strengthen coast guard patrols along critical corridors.With undersea cables serving as "the barbed wire of the 21st century digital order," Hsu said the US has a narrowing window to act before China's gray zone operations become irreversible. He added that Taiwan's own political parties must set aside partisan differences, pass a defense budget, and demonstrate the resolve needed to rally international support.