“Some subjects are so serious that one can only joke about them.”

The Abolition of Work (1985)
Context: These experts who offer to do our thinking for us rarely share their conclusions about work, for all its saliency in the lives of all of us. Among themselves they quibble over the details. Unions and management agree that we ought to sell the time of our lives in exchange for survival, although they haggle over the price. Marxists think we should be bossed by bureaucrats. Libertarians think we should be bossed by businessmen. Feminists don't care which form bossing takes so long as the bosses are women. Clearly these ideology-mongers have serious differences over how to divvy up the spoils of power. Just as clearly, none of them have any objection to power as such and all of them want to keep us working.
You may be wondering if I'm joking or serious. I'm joking and serious. To be ludic is not to be ludicrous. Play doesn't have to be frivolous, although frivolity isn't triviality: very often we ought to take frivolity seriously. I'd like life to be a game — but a game with high stakes. I want to play for keeps.

As quoted in a letter to The Times https://en.wikipedia.org/wiki/The_Times (2018)

Source: World of the Five Gods series, The Curse of Chalion (2000), p. 313

Sometimes attributed to Winston Churchill, it is in fact a slight misquote of "A joke's a very serious thing" from the 1763 poem "The Ghost" by Charles Churchill.
Misattributed

Book IV, line 1386
The Ghost (1763)

Source: Esther: A Novel (1884), Ch. VII

Source: "She Mocked Men’s Bluster. Then Came the Complaints." in The New York Times https://www.nytimes.com/2020/12/30/world/asia/male-confidence-comedian-china.html (30 December 2020)

(17 April 2014) http://on.rt.com/vqds8o
2011 - 2015

The Canton, Ohio Speech, Anti-War Speech (1918)