This is just ever-so-slightly suspect because it isn't *direct* from the source but here is a link to the New York City Opera Learning Resource Center's biography of Wagner, adapted from the Grove Dictionary of Opera, a well-respected reference work that does not, so far as I know, go in for flames or polemics.
I know Larry Sanger wants this sort of thing on the talk pages, but I think it is relevant to the discussion of how far a reference work may go in expressing an opinion or judgement:
http://www.nycopera.com/www/learn/resource/biographydetails.cfm?ComposerID=1...
In this biography, Wagner's essay on Jews in music is described as "ragingly anti-Semitic". The biography further states that as Wagner was completing his final opera, "In the meantime, he continued his musical and polemical writings, concentrating on 'racial purity'."
So, assuming that the quotes are correct, Wikipedia could cop out on this whole thing and quote Grove, but I don't see any problem with our going ahead and stating well-established information directly without weasling.
Tom Parmenter Ortolan88