According to this Guardian article, the National Enquirer has written to Jeff Bezos threatening to publish nude pictures of Bezos unless he stops his investigation into how the Enquirer obtained some private messages.
According to this article by law professor Eugene Volokh in the Washington Post, this is the "paradox of blackmail", where A threatens to do something legal unless B does something else which is also legal. The paradox is, how do we define the crime of blackmail in such a case without also criminalising all sorts of perfectly honest and beneficial behaviour, such as threatening a lawsuit unless stolen money is repaid.
So my question is, assuming the Guardian article and Bezos's assertions are accurate, has the National Enquirer committed the crime of blackmail? I'm specifically interested in whether this is a crime under the relevant laws, rather than whether this falls under the dictionary definition of blackmail.