Ingersoll's heresy was delivered through the most respectable medium his century offered: the paid public lecture. On the circuit he became, by common consent, the greatest orator in the country and one of its most expensive, commanding fees that reached into the thousands of dollars for a single night in an age when a workman earned a dollar or two a day, and filling the largest halls in America for performances delivered without notes.
The repertoire mixed freethought lectures, The Gods, Some Mistakes of Moses, Why I Am an Agnostic, with Shakespeare, Burns and reverent portraits of Lincoln, and audiences who deplored his theology paid to hear the voice; clergy attended, sometimes to answer him the following Sunday, which filled their halls too. The career had a strict boundary.
A brilliant trial lawyer and a loyal Republican whose nominating speech for Blaine in 1876, the Plumed Knight address, became a classic of convention oratory, he was told plainly that public office was closed to him unless he muted his religious views, and he declined the bargain; the offices went elsewhere and the lectures went on. The economics deserve notice because they answered a standing argument: that unbelief could not sustain public virtue or public interest. Ingersoll demonstrated weekly that an avowed agnostic could be the most popular platform figure in a churchgoing nation, provided the agnosticism arrived with wit, and the demonstration was itself his most effective argument.