Last week, President Donald Trump ordered the Pentagon to reduce America’s dependence on foreign mineral suppliers. The military must now map vulnerable supply chains and shift them toward domestic and allied sources.

The next day, the Interior Department acknowledged a critical problem jeopardizing that strategy: Much of the country still lacks the data needed to locate critical mineral resources. That is a basic contradiction in the administration’s strategy. Washington cannot expect itself to prioritize domestic mineral production without first knowing what domestic minerals exist.