The only thing necessary for evil to triumph is for good men to do nothing.Google Books shows an example from a book called Commonism that came out in 1957 (and a quick check of library holdings confirms that a book with that title did come out at that date), but it appears to have been popularized by its inclusion in the 14th edition of Bartlett’s Familiar Quotations (1968). According to They Never Said It, the 1989 compendium of fake quotes, misquotes, and misleading attributions by Paul F. Boller, Jr., and John George (which unfortunately is not always accurate itself) Spiro Agnew speechwriter William Safire challenged Bartlett’s editor Emily Morrison Beck on the source of the speech, and she suggested it might be a paraphrase of something Burke said in a speech on 23 April 1770:
When bad men combine, the good must associate; else they will fall, one by one, an unpitied sacrifice in a contemptible struggle.Safire apparently called this a “pretty long stretch”, and that does seem to be an accurate observation.
In January 2002 Martin Porter (‘All that is necessary for the triumph of evil is that good men do nothing’ (or words to that effect)) did an interesting piece on the variations this quotation had undergone on the web, and on his inability to trace it back to any original source by Edmund Burke. This essay is well worth reading by anybody interested in the uncontrolled transmission of texts, but a follow-up piece (Four Principles of Quotation) contains four rules that ought to be taken into account by anybody passing on a(n alleged) quotation. These are:
(1) Whenever you see a quotation given with an author but no source assume that it is probably bogus.Ah, yes, words to live by.
(2) Whenever you see a quotation given with a full source assume that it is probably being misused, unless you find good evidence that the quoter has read it in the source.
(3) Whenever you make a quotation, give the exact source.
(4) Only quote from works that you have read.