No one in this world, so far as I know — and I have researched the records for years, and employed agents to help me — has ever lost money by underestimating the intelligence of the great masses of plain people. Nor has anyone ever lost public office thereby.
H. L. Mencken (1880–1956) American writer and journalist [Henry Lewis Mencken]
Notes on Journalism, Chicago Tribune (19 Sep 1926)
Popularly, "Nobody ever went broke underestimating the intelligence of the American people."


Please fix the typo. ” Nor has anyone ever…” (not “nyhone”)
Thanks for the spot, Sara. Done.
The newspapers chronicle with degrading avidity the sins of the second-rate, and with the conscientiousness of the illiterate give us accurate and prosaic details of the doings of people of absolutely no interest whatsoever.”
Oscar Wilde, In Conversation