What is considered Blackmail?

Been thinking about this for a while now. Today's article in The Standard about a PhD student blackmailing his teacher got me thinking again, when is it considered illegal to offer something, in return for something (considered blackmailing) and when is it legal to do the same?


David Letterman was blackmailed by Robert Halderman regarding his sexual affairs and subsequently pleaded guilty. My problem is that if Halderman simply exposed the information to the public he wouldn't be committing a crime. Since he "offered" Letterman a chance to cover it up in return for something, he was convicted of blackmail!


Police always offer plea deals to people who assist in their investigation. If you help us we can reduce your sentence, or whatever it is.....is this not blackmail?


From a layman's point of view, I have something you want, do you want it? And what are you willing to offer for it? This sounds simple enough, but is it blackmailing?

Blackmail is the crime of threatening to reveal embarrassing, disgraceful or damaging information about a person to the public, family, spouse or associates unless money is paid to purchase silence. It is a form of extortion. Because the information is usually substantially true, it is not revealing the information that is criminal, but demanding money to withhold it is.

@Krips. PLEA bargain is the wrong description. When prosecution needs a criminal witness to cooperate against another criminal or case, and the option is 1. work with us and get a "deal" or 2. don't work with us and go to prison or stay there longer than necessary.....isn't that "legal blackmail".


And as an example, what if I had an argument with a grocery store clerk. My demand is reasonable but am getting nowhere so I tell them that if they did not do what I'm requesting, I would report to the Food & Environmental Hygiene Department that I saw rats in their store. (Which is a fact!) And I'll also notify the press, not that it's newsworthy. In any case, is that blackmail?


There are many cases of sexually abused individuals when they were young by "persons of authority". They settle out of court and the details or charges and never brought forward. How does that happen without it being considered blackmailing?