"The world is run by those who show up": Source?

I am looking for the original source and correct form of the aphorism that “the world is run by those who show up.” (I have also heard it as “the world is run by those that show up” and “the world is run by those who show up at meetings.”) Any help will be appreciated.

(I apologize if this question has come up before. I am traveling with my laptop and relying on a very slow dial-up connection in my hotel room, so not only can I not check my references on quotations, I can’t run a search on the SDMB without hosing up my connection.)

Thanks!

I at least know the phrase Decisions are made by those who show up. was uttered on The West Wing.