According to Wikipedia (America's online reference for 750 years!) Mike Godwin coined this in 1990.

Here's where I said it in 1989:

Newsgroups: news.groups
From: richard@gryphon.COM (Richard Sexton)
Message-ID: <21000@gryphon.COM>
Date: 16 Oct 89 17:48:06 GMT
Local: Mon, Oct 16 1989 1:48 pm 
Subject: Re: .aquaria
In article <1989Oct16.115545.12...@agate.berkeley.edu> gsmith@garnet.berkeley.edu (Gene W. Smith) writes: 


>  People voted for Hitler as Chancellor too. A vote is not to 
>determine what is best, or what is right, but what is going to 
>happen. A winning vote is not evidence that the winning voters 
>were correct. 

You can tell when a USENET discussion is getting old when one of 
the participents drags out Hitler and the Nazis.

See for yourself in google or read the what happened the day I met Godwin