For more than a century, US courts generally deferred to public health authorities, recognizing their expertise and the necessity of swift, science-based action to protect population health. This deference supported legal interventions that substantially increased life expectancy, reduced morbidity, and advanced health equity. In recent years, however, courts — particularly the Supreme Court — have retreated from this approach. Specifically, Supreme Court–driven doctrinal shifts favoring free exercise challenges, limiting deference to administrative agencies, and undermining equal protection have eroded public health authority and constrained governments’ capacity to protect health and improve equity. Drawing on an empirical review of 30 lawsuits filed between January 2024 and May 2025 challenging governmental and institutional health equity initiatives, the paper demonstrates that the majority of these cases resulted in the invalidation or abandonment of equity-focused policies. These findings illustrate how contemporary judicial rulings are limiting governments’ and institutions’ authority and ability to safeguard health, particularly the health of our most vulnerable and marginalized populations. The paper concludes with a call to action: a coordinated public health strategy to build and sustain a jurisprudence that supports the fair, effective, and evidence-based exercise of public health authority.