On March 9, 2021, the County of Santa Clara filed a federal lawsuit with tribal, health care practitioner, and nonprofit partners challenging a midnight Trump Administration rule that added “expiration dates” to approximately 18,000 U.S. Department of Health and Human Services (HHS) regulations. Under the deregulatory rule, nearly every single HHS regulation will automatically expire, starting in five years, unless HHS diverts its resources from Biden Administration priorities, such as responding to the COVID-19 pandemic, to instead conduct time- and resource-intensive regulatory reviews. To prevent expiration of 17,200 separate HHS regulations in 2026, HHS would need to review its regulations at a pace over 20-times greater than it has ever achieved before. HHS does not guarantee that it can or will complete the reviews necessary to prevent the “unprecedented” rule from causing mass regulatory expiration. If allowed to take effect, the rule will cause immense chaos and harm to the County’s health system while the country is in the midst of the ongoing COVID-19 pandemic. The County is challenging the rule, together with Democracy Forward, the California Tribal Families Coalition (CTFC), the National Association of Pediatric Nurse Practitioners (NAPNAP), the American Lung Association, the Center for Science in the Public Interest (CSPI), and Natural Resources Defense Council (NRDC).