Should Blackmail Be a Crime?

You've probably heard the big story about the attempted blackmail of David Letterman. A CBS News producer threatened to release information about Letterman having had sexual relations with some of his female staff unless Letterman paid him $2,000,000. Letterman told his lawyer,
his lawyer set up meetings with the would-be blackmailer and contacted the authorities, and the end result was that the blackmailer was arrested after Letterman testified before a grand jury. Then, last night, Letterman disclosed all of this during a segment of "The Late Show."

I don't know when Letterman, who recently married a woman with whom he's been involved for over twenty years and has one child with her, had these sexual encounters with female staff members. And my purpose in bringing up this story is not to discuss the morality of his sexual
behavior. I want to discuss something else.

First off, I'm glad he reported the blackmail attempt to the authorities instead of paying the money. I despise blackmail, and, if there's going to be a law against it, then I want it socked to anyone and everyone who tries to perpetrate it. But, having said that, when I ask myself if
blackmail should be prohibited by law, I feel a little perplexed. Why? Because, if you really think
about it, even though blackmail seems morally reprehensible, does its egregiousness rise to the level of criminality?

Well, obviously it DOES rise to it in the sense that it IS a crime. But SHOULD it be a crime? After all, if the guy who tried to blackmail Letterman had simply released the information he threatened to release without demanding money not to release it, there's no law against THAT.
So, why IS there a law against the extra component of asking for money not to release the information?

Of course, blackmail is a form of extortion. But extortion can include threatening to do something ILLEGAL to someone if one isn't compensated in some way for not doing it. But, again, releasing information to the public about an adult's sexual escapades is not illegal in and of itself, so why should threatening to do something legal if one isn't paid not to be a crime?

I'm not saying that I feel convinced that there shouldn't be such a law. On an emotional level, I'm glad this guy got arrested, and I hope he spends the next few years in prison and that others are deterred from trying to do what he did. But, on an intellectual level, I'm not sure I
can justify making blackmail a crime. Can you?

What do you think?