"What is history but the story of how politicians have squandered the blood and treasure of the human race?"
Thomas Sowell in Is Reality Optional?

"If you subsidize a thing, you’re going to get it."

Dinesh D’Souza in Chronicles magazine September 1991.

"Cleverness is serviceable for everything, sufficient for nothing."

Henri-Fréderic Amiel in Journal intime
 

"But, when infection is about, an open mind is about as safe as an open sewer."

Nicholas Murray in The Sunday Times April 7, 2002 (specifically re Aldous Huxley succumbing to so many cranky notions before and after moving to California) 

"The object of philanthropy is to do good; the object of religion is to be good, if only for a moment, amid a crash of brass."

G.K. Chesterton in Heretics
GKC Heretics

"I sleep like a baby, too. Every two hours, I wake up screaming."

Then U.S. Secretary of State Colin Powell, re reports that President George W. Bush had slept like a baby in the runup to the Iraq war, quoted in Globe and Mail Nov. 16, 2004 (I swear I thought of this joke years earlier but Powell beat me into print and may himself have come up with the gag long before)

"[T]he only thing in life which is interesting is truth, and the only thing in life which is admirable is goodness."

Malcolm Muggeridge "About Kingsmill" in Ian Hunter, ed., The Very Best of Malcolm Muggeridge

"A common error, however, is to regard the civilizing process and the humanizing process as synonymous. A correlation between the two has yet to be demonstrated. (The first glance was enough to let you see the flabby devil was running that show.)"

Mark Slade in Mosaic magazine (re Conrad’s Heart of Darkness), quoted in Marshall McLuhan “Man and Media” in McLuhan Understanding Me 295.