WornOutGrunt 2

I agree 100% that CIA used it as a weapon to attack anyone who questioned the Warren Commission narrative.

The term "conspiracy theory" first appears in the United States in 1863.

The Oxford English Dictionary identifies the earliest known use as a letter to the editor by American author Charles Astor Bristed, published in The New York Times on January 11, 1863 (some accounts reference related coverage around January 4). Bristed used it in discussing claims that British aristocrats were deliberately weakening the United States during the Civil War for their financial interests: people “only look at the sudden right-about-face movement of the English Press and public, which is most readily accounted for on the conspiracy theory.”

Merriam-Webster also lists the first known use as 1863. Newspaper archives show the phrase appearing in U.S. papers from the 1860s onward (with additional early examples around 1868 in places like the Boston Post). It saw wider use in reporting after the 1881 assassination of President James A. Garfield, in discussions of whether the assassin had accomplices.

Context and later developments

In the 19th century the phrase was often used neutrally or forensically (e.g., a “conspiracy theory” of a crime meaning the hypothesis that more than one person was involved). It later appeared in historical and political writing. Philosopher Karl Popper discussed the broader “conspiracy theory of society” in The Open Society and Its Enemies (1945). Usage increased in the mid-20th century; the related term “conspiracy theorist” appears by the early 1960s (before the JFK assassination).

A common claim that the CIA invented or first popularized the term in a 1967 memo (“Countering Criticism of the Warren Report”) to discredit critics of the Warren Commission is false. The phrase long predates the CIA (founded 1947) and the memo, which simply used an already-existing expression. Fact-checks by Snopes, AP News, and others document this clearly through dictionaries and newspaper archives.

Key sources

Oxford English Dictionary entry for “conspiracy theory” (earliest evidence 1863, New York Times).

Merriam-Webster Dictionary (first known use 1863).

Snopes fact-checks (detailed archival evidence from the 1860s onward and debunking of the CIA invention claim).

AP News fact-check (1863 New York Times letter; wider use after Garfield’s 1881 shooting).

Grammarphobia analysis of early newspaper examples (including 1868 U.S. usage).

Research by Andrew McKenzie-McHarg on the 19th-century history of the term (noted in AP and academic discussions).