excerpt from site
"When bad men combine, the good must associate; else they will fall one by one, an unpitied sacrifice in a contemptible struggle."
That quote from Edmund Burke in "Thoughts on the Cause of Present Discontents" has, in general use, come to be delivered as, "The only thing necessary for the triumph of evil is for good men to do nothing."
There's more written about it there. The url is http://davidsisler.com/2-17-96.htm
When googling for info for my email I came across lots of sites with variations on the quote, and one very good one that went through all of the stuff online that was innacurate or incomplete or contradictory about this quote and Burke. I believe that it was Burke, but because there was reasonable argument about the attribution I decided to fudge in my attribution so that I couldn't be blind sided with some web page that declared that the quote wasn't "really" from Burke as a way to refute my argument.
I've checked your link and it's a goody. Burke is one of the good guys. Thanks for the reference. I've saved the page.