False Marg. Mead quote? "Never doubt...."

[James W. Harris]

"Never doubt that a small group of thoughtful, committed
persons can change the world. Indeed, it's the only
thing that ever has..."

The quote is ATTRIBUTED to Margaret Mead, the anthropologist.
I say ATTRIBUTED because I believe I've read somewhere
that the quote may be inauthentic. I'm simply not
sure.

Anyone know one way or the other?

If you could email me a response as well as posting
it here, I'd be most appreciative!

Thank you,

James