Ta-Chen Chen, Non-Resident Fellow of the National Security Program at the Research Institute for Democracy, Society and Emerging Technology (DSET), was interviewed by TaiwanPlus to share insights from his newly released policy report, Undercurrent: Limits and Prospects of Submarine Cable Security for Taiwan. In the interview, Chen analyzed the escalating threats to Taiwan’s subsea cable security and emphasized that for democratic states, the priority is to maintain legitimacy and respond within existing international norms and frameworks.
When asked how this principle can be applied in practice, Chen explained that democratic countries must act in accordance with international norms to ensure that their policies are lawful, reasonable, and built on reliable foundations. “This is essential not only for the support of the international community, but also for the trust of domestic audiences,” he noted.
When discussing policy recommendations, Chen emphasized that policymakers must obtain concrete and sufficient evidence to clearly establish both the state affiliation of the vessels involved and whether their actions constitute gray zone activities.
He pointed out that the legal threshold for attribution under international law is extremely high. While customary international law allows for countermeasures, their scope and strength must be determined case by case, and “the precondition is having the right and sufficient evidence.”
In response to questions about how Taiwan could counter potential cable-cutting operations by China, Chen cautioned against using “gray zone” as a blanket label, which risks imprecise policymaking. Instead, Taiwan must strengthen intelligence collection and make use of tools available under international norms to propose neutral and actionable responses. At the same time, he emphasized the importance of enhanced information sharing with allies to build consensus and secure broader international support.
The report identifies three policy tracks for Taiwan and its allies: punishment, which relies on concrete intelligence to attribute vessels to gray zone actors and invoke countermeasures under international law for unilateral jurisdiction; offset, which employs unilateral tools or allied coordination in international forums to impose stricter regulatory burdens, such as port state measures or IMO cooperation, thereby diminishing political gains; and address, which holds flags of convenience accountable through international agreements, enabling collective jurisdiction or investigation over cable damage, with the long-term goal of securing broad consent from flag states and constraining the maneuvering space of gray zone actors.