Kathy is forty$-$two $(42)$ years old and has been diagnosed with a rare case of early$-$onset Alzheimer's disease. While there are drugs that can control her condition, there is no known cure. When she reads a newspaper article that a claimed cure has been discovered in Sweden, she requests the drug from her doctor, who informs her that the drug is not legal in the United States and cannot be purchased outside of Sweden. Kathy files a lawsuit in federal court to allow her to purchase and use the drug. The federal district court determines that the case must be suspended and referred to the Food and Drug Administration $($FDA$)$ for initial review and determination. What is the requirement that the district court judge is following?