"When Prohibition was introduced, I hoped that it would be widely supported by public opinion and the day would soon come when the evil effects of alcohol would be recognized. I have slowly and reluctantly come to believe that this has not been the result. Instead, drinking has generally increased; the speakeasy has replaced the saloon; a vast army of lawbreakers has appeared; many of our best citizens have openly ignored Prohibition; respect for the law has been greatly lessened; and crime has increased to a level never seen before."
John D. Rockefeller, one year before prohibition ended in 1933.
Now substitute drugs.
This letter is quoted by David Borden, Executive Director of Stop the Drug War.org. in his editorial, How Long Does an Experiment Need to Continue Before It's Declared a Failure? Check it out.
Thanks for the tip, Cliff Thornton at Efficacy.