Rare earth elements are used in everyday products: smart phones, hard disc drives, flat-screen televisions and advanced batteries. They are essential to such “green” technologies as wind turbines, compact fluorescent lights and hybrid cars. In today’s world, which emphasizes cutting-edge and environmentally-friendly technologies, rare earths are everywhere. Furthermore, a range of highly advanced defense systems, such as Ground Laser Target Designators and advanced jet aircraft, depend on rare earth phosphors, metals, alloys and magnets for their unique functionality. This issue brief examines possible shortages of some rare earths, therefore, threaten our nation’s defense systems.