The term "witch hunt"

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Former US president Donald Trump says the Senate impeachment trial has been another phase of the "greatest witch-hunt in the history of our country".

Is this appropriate use of the term? I always thought that a witch hunt involved a theory of a giant conspiracy, and large number of people being accused, such as McCarthyism. Can you have a witch hunt directed at one person?

Edit. Part of the term "witch hunt" is the word "hunt" which I think is the important part. McCarthyism was a search for unknown persons. It was the suspicion that there were many unknown persons in a great conspiracy. People were questioned to find out if they were part of it. Always the suspicion that there were more people, still unidentified, who must be found. It was a search. It was a hunt.

Can a witch hunt be directed against a single known person whose activities are mostly already know? Is that even a hunt at all?

(No political commentary, please. This is not a debate about whether the charges in a particular case were merited or not. It is just about the use of the word.)