Knowledge of what?
Senate rules he invented?
Oratory skills?
To ramble endlessly about his dog while he filibustered civil rights?
Come on!
The man literally wrote the book, make that a 4 volume set of books on the history of the Senate. He had an intimate knowledge of the Senate rules, and yes after that length of service he he did have a hand in writing them, but that does not take away from his knowledge.
he was also the staunchest supporter of the 1st amendment, and was the only Senator to admonish Bill Clinton about attempting to influence the Jury (Senate) during his impeachment.