The Centers for Disease Control and Prevention was once the world’s most trusted guardian of public health. Its mission—protecting Americans from infectious disease—was clear and noble. But over the decades, bureaucratic inertia, politicized science and mission creep have corroded that purpose and squandered public trust. That dysfunction produced irrational policy during Covid: cloth masks on toddlers, arbitrary 6-foot distancing, boosters for healthy children, prolonged school closings,...