> The earliest known usage was by the American author Charles Astor Bristed, in a letter to the editor published in The New York Times on January 11, 1863.
> The term "conspiracy theory" is itself the subject of a conspiracy theory, which posits that the term was popularized by the CIA in order to discredit conspiratorial believers, particularly critics of the Warren Commission, by making them a target of ridicule.
> the term was popularized by the CIA in order to discredit conspiratorial believers, particularly critics of the Warren Commission, by making them a target of ridicule.
Who popularized it is subjective.
What isn't subjective: the CIA indeed sent out a memo about this. It marked an increase in the use of the term in popular media publications. You can find it and read it.
https://en.wikipedia.org/wiki/Conspiracy_theory#Origin_and_U...
> The earliest known usage was by the American author Charles Astor Bristed, in a letter to the editor published in The New York Times on January 11, 1863.
> The term "conspiracy theory" is itself the subject of a conspiracy theory, which posits that the term was popularized by the CIA in order to discredit conspiratorial believers, particularly critics of the Warren Commission, by making them a target of ridicule.