A bipartisan group of six US senators has urged the Trump administration to urgently protect domestic production of silicon carbide, warning that China has rapidly seized control of a semiconductor material considered indispensable for advanced weapons systems, artificial intelligence infrastructure, and the electric grid. The letter, dated 1 October 2025 and released on Friday, 3 October, marks one of the most direct congressional calls for a 'whole-of-government' response to Beijing's push to dominate the global silicon carbide supply chain.

Who Signed and What They Are Asking

The appeal was signed by senators Tom Cotton and John Boozman of Arkansas, Chuck Schumer of New York, Thom Tillis and Ted Budd of North Carolina, and Mark Kelly of Arizona — spanning both the Republican and Democratic parties. The senators addressed their letter jointly to Defence Secretary Pete Hegseth and Commerce Secretary Howard Lutnick, calling on them to deploy every available federal authority to shore up American and allied manufacturing of the material.

The lawmakers specifically asked the administration to consider leveraging Defence Production Act authorities, critical minerals designations, Buy America requirements, and any other tools at its disposal. Notably, the letter did not prescribe a single remedy, instead urging a broad-based inter-agency approach.

The Scale of China's Market Advance

The senators cited stark figures to underscore the urgency. According to the letter, Chinese producers expanded their share of the global silicon carbide wafer market from less than 5 per cent to nearly 50 per cent in just five years — a pace of market capture that the senators linked directly to Beijing's Made in China 2025 industrial strategy. The senators argued that China had deliberately identified silicon carbide's military and economic significance and made dominance of the sector a national priority.

'Clearly, China intends to undermine another strategically important industry built on American technology and ingenuity,' the senators wrote.

Why Silicon Carbide Is Strategically Critical

Silicon carbide is a foundational material for a class of next-generation power semiconductors. Its capacity to withstand extreme voltages and temperatures while enabling rapid electrical switching makes it especially valuable for defence applications. The senators described it as 'irreplaceable in high-performance air, land and sea propulsion systems, directed energy weapons, and air and missile defence systems.'

Beyond defence, silicon carbide is embedded across sectors with deep national security implications — including AI data centres, electric grid infrastructure, 5G telecommunications, and the automotive industry. The senators warned that if China's campaign in the sector succeeds, the United States will find itself reliant on adversary supply chains for components essential to its most advanced defence systems and critical technology infrastructure.

The Urgency Behind the Letter

The senators acknowledged that the American supply chain is already under significant pressure and warned of a shrinking window for corrective action. 'The time to act is now, before we reach the crisis stage where remedies are impossible or far more expensive and time-consuming,' they wrote.

This comes amid a broader congressional pattern of concern over US dependence on China for critical materials and technologies, from rare earths to advanced chips. Silicon carbide now joins that list with particular urgency given its direct military applications. The letter is the latest signal that semiconductor supply chain security — long a bipartisan concern — is intensifying as a legislative priority ahead of potential new trade and defence policy measures.