critical materials, including rare earth elements (ree) and strategic metals, are essential for technologies used in a variety of applications such as cell phones, computers, cars, airplanes, batteries, and renewable energy systems – and therefore critical to our national security and economy. the united states is not self-sufficient in most of these critical materials, and for many of them we are reliant on foreign sources prone to disruption. for example, more than 97 percent of the u.s. and world supply of ree comes from china, and this supply has been restricted recently for several reasons, including political pressure. american policymakers can take action to strengthen american expertise in the occurrence, discovery, extraction, processing, and recycling of these commodities.