If voting changed anything, it would be made illegal.
Source, in full
Although often attributed to Goldman, there is no evidence that she made such a statement. The earliest known example of this quote is from a 1976 newspaper opinion piece by Robert S. Borden, in "Voting is Dishonest and Fraudulent", The Sun {Lowell, Massachusetts} (24 September 1976), p. 7: "If voting could change anything, it would be made illegal". According to Snopes.com, this and similar statements are also incorrectly attributed to American humorist Mark Twain or American peace activist Philip Berrigan.
Notes from Wikiquote
If voting changed anything, they'd make it illegal. | If voting changed anything, it would be illegal. | If voting made a difference, it would be illegal. | If voting made any difference, they wouldn't let us do it. | If voting mattered, they wouldn't let us do it.