Opening Perspective
Spymaster: Did you dig up something I can use against Firefly?
Chico Marx: We follow him to a roadhouse where he meets a married lady

Spymaster: A married lady? Now we are getting somewhere.
Chico Marx: Yeah. I think it was his wife.

Spymaster: Firefly has no wife.
Chico Marx: No?
Spymaster: No
Chico Marx: Then you know what I think, Boss?
Spymaster: What?
Chico Marx: I think we follow the wrong man.


INTRODUCTION
The term "blackmail" has been attached to a number of relations where one person extracts something of value from another with
pressure.
My concern here is limited to "pure" or "informational" blackmail: the sale of silence by someone who is otherwise free to
disclose what he knows.

The cast of characters in a blackmail must
number at least three. I call them "A," "B," and "C." "B" (for "blackmailer" is the holder of information that he threatens to
disclose unless compensated.

"A" is the person to whom B offers to
sell his silence, and is usually the subject of the information to be kept silent. "C" is the person or persons to whom B threatens to disclose the information, absent agreement with A.

"C" may be an individual, a group, the public, or a representative of the public such as a prosecutor. In this triangle, B is an intermediary who, depending on the legal regime, may advance or impede the flow of
information concerning A to C.

A key element of "pure" blackmail, which has led some to question whether it should be treated as a crime, is that B is initially
free to make the disclosure over which he bargains with A.
Blackmail, as addressed here, does not include threats of disclosure barred by statute or contract, such as a doctor's threat to reveal a
patient's loathsome disease, which belong to the broader class of

" Extortion, obtaining something with the threat of inflicting unlawful harm, is a form of theft by force. Much violent crime has an element of extortion. "Kiss me or I will kill you" is a threat to do something that is no more permitted absent the threat than with it.

In contrast, B's bargaining lever in blackmail is
something that normally is within B's right. The criminal prohibition of blackmail-essentially a prohibition on bargaining between B and A over control of information-denies B the right to seek compensation from A for not doing something B is otherwise free
to do.