The Pentagon is considering making prevention, particularly vaccination, optional, a move that represents a misunderstanding of military readiness and force protection. Dr. Richard Carmona, a decorated combat veteran of the U.S. Army special forces, argues that military readiness is built on discipline, leadership, and adherence to evidence-based practices that protect the force and ensure mission success. He argues that public health policy challenges the effectiveness of prevention and calls for better communication, education, and leadership. The principle of prevention is not new, but established in the American military tradition of using science-based prevention.