“Have you heard that expression used before? Because I haven't heard it. I mean, I just… I came up with it a couple of days ago and I thought it was good. It's what you have to do.”

Interview with Bill Kristol (March 2017)

Source: The Bridge Across Forever (1984), Ch. 21

News Conference of (11 August 1954) http://www.presidency.ucsb.edu/ws/print.php?pid=9977
Variant: When people speak to you about a preventive war, you tell them to go and fight it. After my experience, I have come to hate war. War settles nothing.
Quoted in Quote magazine (4 April 1965) and The Quotable Dwight D. Eisenhower (1967) edited by Elsie Gollagher, p. 219<!-- seldom found variants: All of us have heard this term 'preventative war' since the earliest days of Hitler. I recall that is about the first time I heard it. In this day and time... I don't believe there is such a thing; and, frankly, I wouldn't even listen to anyone seriously that came in and talked about such a thing.
A preventative war, to my mind, is an impossibility. I don't believe there is such a thing, and frankly I wouldn't even listen to anyone seriously that came in and talked about such a thing.-->
1950s
Context: All of us have heard this term "preventive war" since the earliest days of Hitler. I recall that is about the first time I heard it. In this day and time, if we believe for one second that nuclear fission and fusion, that type of weapon, would be used in such a war — what is a preventive war?
I would say a preventive war, if the words mean anything, is to wage some sort of quick police action in order that you might avoid a terrific cataclysm of destruction later.
A preventive war, to my mind, is an impossibility today. How could you have one if one of its features would be several cities lying in ruins, several cities where many, many thousands of people would be dead and injured and mangled, the transportation systems destroyed, sanitation implements and systems all gone? That isn't preventive war; that is war.
I don't believe there is such a thing; and, frankly, I wouldn't even listen to anyone seriously that came in and talked about such a thing.
… It seems to me that when, by definition, a term is just ridiculous in itself, there is no use in going any further.
There are all sorts of reasons, moral and political and everything else, against this theory, but it is so completely unthinkable in today's conditions that I thought it is no use to go any further.

"The Real-Life Diet of JaVale McGee, Vegan" https://www.gq.com/story/javale-mcgee-real-life-diet, interview with GQ (February 27, 2018).

Attributed to Greenspan by Rupert Cornwell, "Alan Greenspan: The buck starts here" http://www.independent.co.uk/news/people/profiles/alan-greenspan-the-buck-starts-here-595789.html, The Independent, 27 April 2003, citing an unspecified Capitol Hill hearing. However, as Ralph Keyes notes in The Quote Verifier (2006, p. 233), "This popular tongue twister gets attributed to the obfuscator du jour." The earliest known print attribution is to Robert McCloskey, U.S. State Department spokesman, by Marvin Kalb, CBS reporter, in TV Guide, 31 March 1984, citing an unspecified press briefing during the Vietnam war.
Earlier attributions include: "a high government official", Annual Report, North American Gas Tax Conference, Federation of Tax Administrators, 1967; Jerry Lewis (a sign pasted on the camera during a movie shoot), by Dick Kleiner, Hollywood Correspondent, Sumter Daily Item, Feb. 4, 1970; a sign on the desk of Suzanne Schroeder, collector of bureaucratic gobbledygook, AP wire story, Sarasota Herald-Tribune, July 3, 1973; Jack Nicklaus paraphrasing Richard Nixon, by Larry Dorman, The Palm Beach Post, Dec. 8, 1979; and "a Hollywood film director", by J.D. Douglas, The Third Way, 29 December 1977. Additionally, a thesis monograph by Michael David Katz, Georgia State University, 1973 is titled with the quote.
On the back of the first Stealers Wheel album, a very similar statement attributed to band member Rod Coombes is found: "We know that you believe you understand what you think we said, but we are not sure you realize that what you heard is not what we meant." The album was released in 1972.
See Richard Nixon: "Now, when individuals read the entire transcript of the [March] 21st [1973] meeting, or hear the entire tape, where we discussed all these options, they may reach different interpretations, but I know what I meant, and I know also what I did"
Misattributed

Ellen DeGeneres' interview with The Four Agreements Author don Miguel Ruiz which appeared in the October 2001 issue of O, The Oprah Magazine

Source: The Princess Bride

“Just so.”
Part IV, Chapter V (p. 392)
The Privilege of the Sword (2006)

Source: The Handmaid’s Tale (1985), Chapter 30 (pp. 192-193)
Source: The Handmaid's Tale
Context: I'll take care of it, Luke said. And because he said it instead of her, I knew he meant kill. That is what you have to do before you kill, I thought. You have to create an it, where none was before. You do that first, in your head, and then you make it real.