The United States still possesses the world’s most formidable military. It fields the most advanced aircraft, the most sophisticated satellites and a nuclear arsenal of unmatched technological complexity. Yet, according to a warning delivered this week by lawmakers in Washington, that vast architecture of power depends on something far less visible: critical minerals — rare earth elements, lithium, cobalt and other strategically vital materials — pulled from the earth, refined in foreign facilities and shipped across sea lanes the United States may not always be able to guarantee.

Beneath the circuitry of precision weapons and the composite skins of stealth aircraft lies a supply chain rooted in geology, and increasingly, in geopolitical risk.

At the centre of the concern is China’s overwhelming dominance of critical minerals, a category of materials that rarely feature in political speeches but sit quietly inside almost every modern weapons system. From rare earth elements used in radar arrays and precision-guided munitions to lithium, cobalt and graphite essential for batteries, electric propulsion and sensors, these resources form the hidden infrastructure of 21st-century warfare.

Members of Congress, speaking in hearings and policy briefings, warned that the Pentagon’s industrial supply chains could be severely disrupted in a geopolitical crisis. The fear is not theoretical. American defence planners increasingly view a conflict in the Indo-Pacific — particularly one involving Taiwan — as a plausible contingency. In such a scenario, shipping lanes, export permissions and industrial capacity could all change overnight.

China does not merely mine many of these materials; it refines them. That distinction matters. Mining accounts for only the first step in the supply chain. Processing — separating, purifying and converting minerals into usable industrial inputs — is the stage where China’s dominance becomes decisive. In several rare earth categories, analysts estimate China controls a vast majority of global refining capacity.

This leaves American defence manufacturers in an uncomfortable position. A fighter jet’s stealth coating, a missile’s guidance system and a submarine’s sonar may be designed and assembled in the United States, but key components rely on materials that, directly or indirectly, pass through Chinese industrial networks.

Pentagon officials have long acknowledged the vulnerability, though the urgency of their language has sharpened in recent years. The United States cannot quickly substitute these materials with domestic alternatives. Developing mines is slow, environmentally contentious and financially uncertain. Even when deposits exist — as they do in parts of the American West — building processing facilities can take a decade or more.

The problem is structural. For decades, the United States allowed its mining and processing sectors to shrink as globalization lowered costs and concentrated industrial capacity abroad. Companies followed the logic of markets: Chinese refineries were cheaper, faster and already integrated into global manufacturing. Defence contractors, though operating in a national-security sector, remained part of that economic system.

Now the geopolitical environment has shifted. The war in Ukraine demonstrated how rapidly supply chains can fracture when sanctions, blockades and export controls enter the equation. European defence industries discovered shortages in explosives, propellants and even basic artillery components. American officials see a parallel risk in minerals — only this time the bottleneck would lie at the beginning of the production process rather than the end.

Some lawmakers are urging aggressive intervention. Proposals include federal subsidies for domestic mining, strategic stockpiles of rare earths and closer coordination with allies such as Australia and Canada, both of which possess significant deposits. Others argue for industrial partnerships across NATO and the Pacific, effectively creating a mineral security alliance to counterbalance China’s leverage.

Yet the challenge extends beyond extraction. Refining capacity requires chemical expertise, infrastructure and a workforce that the United States has not cultivated at scale for a generation. Rebuilding it would resemble the re-industrialization projects once associated with wartime mobilization rather than peacetime market policy.

China’s position, meanwhile, was not accidental. Beginning in the late 20th century, Beijing invested heavily in mineral processing, often tolerating environmental damage that Western governments were unwilling to accept domestically. Over time, the country became the default global supplier. The world’s technology industries — smartphones, wind turbines, electric vehicles and weapons systems alike — adapted to that reality.

Military planners worry about what happens if that reality changes abruptly. China would not need to impose a sweeping embargo to create disruption. Even partial export restrictions, licensing delays or targeted sanctions could slow production lines for missiles or aircraft. Modern defence manufacturing operates on precision schedules; interruptions cascade quickly.

The issue also underscores a broader transformation in warfare. The decisive resources of conflict are no longer only oil and steel but data, semiconductors and specialized minerals. Supply chains now function as strategic terrain. Control over materials can shape military readiness as surely as troop deployments.

For American policymakers, the dilemma is immediate but the solution is generational. Mines cannot be opened overnight. Refineries cannot be staffed instantly. And global markets cannot be reordered without economic consequences. The United States must decide how much independence it is willing to purchase, and at what cost.

In Washington, the debate has begun to sound less like trade policy and more like contingency planning. The question is no longer whether the military needs critical minerals — it does — but whether a superpower can safely rely on an industrial ecosystem largely beyond its own borders.

The weapons of the future may be designed with artificial intelligence and built with advanced robotics. But their foundations, lawmakers now caution, still lie deep underground — and, for the moment, much of that ground is controlled elsewhere.

How China Is Systematically Undermining Western Security