I'm not sure I'd accept the family's statement at face value. In fact that's the statement I'd expect out of them completely orthogonally to it's veracity.

Additionally I don't find the subsequent argument compelling. 'Sure Nixon hated hippies and blacks, but it wasn't an effective policy until workshopped by subsequent presidents, so targetting those groups couldn't have been the point" doesn't really hold a lot of weight for me.

On top of all of that, corroborating quotes seem to keep being removed from that wikipage, with an edit note that doesn't match the edit, pointing to brigading.

Interesting, would you mind to point to one of such edit you mention? I cannot see to what you refer. I see removal of newsmax URL few times, however that linked article is not supporting of Harper's original as I read. Perhaps I am not viewing enough backwards in history.

I don't see what's dubious about it. There doesn't seem to be any evidence the quote was fabricated, and the effects of US drug policy are apparent to anyone who lifts their head out of the sand.

You don't think Nixon could have disliked blacks, hippies, and drugs, and just found a convenient way to tie them all together while at the same time being able to say "think of the children?" Nixon was many things, but dumb and politically naive are not among them.