Opinion: The cables beneath the Strait of Hormuz are a national security test

In March, I sat before the U.S.-China Economic and Security Review Commission and described a vulnerability most Americans do not consider: Undersea fiber-optic cables. Roughly 95 percent of the world’s data, from financial transactions to daily messages, travels through these cables worldwide. They are thin, fragile and almost entirely unprotected from either seismic activity or deliberate sabotage by bad actors. 

Taiwan itself is connected to the world by 24 of these cables, landing at just eight stations. I told the commission what our own modeling shows: Severing three key cable clusters near the Bashi Channel would eliminate nearly all of Taiwan’s digital bandwidth almost instantly. The economic damage from cutting Taiwan’s digital lifelines amounts to an estimated $55 million daily, though that figure doesn’t include the effects of a stalled semiconductor supply chain. Taiwan owns no dedicated cable-repair ship, and the global repair fleet averages more than 40 days to fix a single break. 

Such sabotage has already taken place. Since 2023, vessels flying under flags of convenience but manned by Chinese crews have repeatedly dragged their anchors across the cables linking Taiwan to its outer islands and to the world. Sometimes these cables have been cut, resulting in significantly slower communication and Wi-Fi speeds on the outer islands, such as Penghu and Kinmen. 

These acts of sabotage are part of China’s continued gray-zone warfare meant to undercut Taiwanese sovereignty through actions designed to stay just below the threshold of war, to avoid both attribution and consequences. 

This is not only happening in Taiwan. The Baltic Sea has also become a laboratory for this kind of sabotage from the Finland-Estonia EstLink2 power cable to the C-Lion1 line between Finland and Germany. Several of these incidents have been suspected of involving shadow-fleet vessels tied to Russia. Northern Europe and East Asia now face the same shadow war, waged by partners who learn from one another.  

That is why I urged, back in March, Congress to act by passing the Strategic Subsea Cables Act, introduced by Sens. John Barrasso (R-Wyo.) and Jeanne Shaheen (D-N.H.). The Senate Foreign Relations Committee passed it unanimously in January. Now, its text has been folded into the fiscal year 2027 National Defense Authorization Act as a bipartisan amendment. How the bill passes means little, so long as it passes in time, given the urgency of this dual threat.  

The bill is largely unchanged in the defense spending bill. It still requires the president to impose blocking sanctions and revoke the visas of foreign persons and vessels responsible for sabotaging undersea infrastructure, while also punishing the insurers, flag registries, port operators and the captains who make this shadow fleet function. It also establishes a single interagency committee to coordinate among a dozen federal offices for this issue. Finally, it commits the United States to doing what only it can: leading its allies in hardening this infrastructure and speeding up repairs. 

Skeptics may note that while this bill may discourage such actions, attributing them is genuinely difficult, and some of these incidents may be due to crew negligence rather than deliberate sabotage. That is precisely why intelligence is important: to properly identify the saboteurs and work with allies to ensure attribution. And once attribution can be made, the crew can have their visas revoked, their ship sanctioned and their operations denied. The bill builds both the evidence base and deterrence against bad actors seeking to harm international communications.   

Time is of the essence to pass this bill. China has launched a new generation of vessels purpose-built for seabed operations, and their capabilities suggest they are primarily designed for undersea cable sabotage. While the defense spending bill must be passed annually, continued delays in its passage will harm U.S. and allied readiness for this vital infrastructure. Every month Washington delays is a month in which the cost of cutting a cable remains effectively zero.  

I have spent my career between Taipei and Washington, and I have learned that credibility is built on follow-through. Our allies across the Indo-Pacific and Europe are watching to see whether the United States will match its rhetoric about “critical infrastructure” with a concrete call to action. 

While my testimony focused on Taiwan, we are not the only targets; Japan, the Philippines, Australia and the Baltic states are all exposed to the same vulnerabilities. American leadership here is a linchpin of a shared defense, and acting on this issue will more than pay for itself from repair savings to protecting the infrastructure that protects our vital communications. 

The cables beneath the Taiwan Strait and beneath the Baltic are a test of whether free societies can protect what sustains us. The Strategic Subsea Cables Act is the right answer to that test. While the Senate has already shown it agrees by an overwhelming bipartisan margin, it is still crucial to have this passed and sent to the president’s desk, whether as its own bill or through the defense spending bill. 

The next cable cut is coming; the only question is whether the U.S. will make them pay a price for it.

Jason Hsu is a senior fellow at the Hudson Institute and a former member of Taiwan’s Legislative Yuan. 

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