In 1813, the American government passed An Act to Encourage Vaccination, the first federal endorsement of a medical practice in American history. The law tasked a federal agent with maintaining a supply of the smallpox vaccine and distributing it nationwide. James Smith, a well-respected physician and proponent of vaccination, was appointed as vaccine agent. Smith was skeptical of claims that only well-trained physicians should be allowed to perform vaccination; he felt it was a simple procedure that should be available to all American citizens. In 1822, he made a tragic error that caused several deaths and left him vulnerable to criticism from political opponents and his medical peers. This ended Smith's professional career and led to the repeal of the act itself. In this article, we use the rise and fall of James Smith to provide a historical perspective on contemporary debates surrounding delayed vaccination schedules. We explain how physicians-in the 19th century and today-have worked to build public trust in vaccination in an American culture suspicious of medical expertise.