The first thing that occurred to me when I read about Clint Eastwood debating an empty chair was that I had heard this story before ...
And I had.
Arthur M. Schlesinger, Jr., in Robert Kennedy and His Times, wrote about the televised 1964 U.S. Senate debate between Sen. Ken Keating (R-NY) and an empty chair, representing Robert F. Kennedy's supposed "ruthless contempt" for the voters of New York.
Schlesinger called Keating's move an "ancient device," but doesn't give us the history of the empty chair stratagem.
You all know what they say about those who cannot remember the past ...