Elizabeth Ann Thrasher is being prosecuted under the Missouri felony harassment statute passed in the wake of the Lori Drew case. The St. Louis Post-Dispatch reports:

Elizabeth A. Thrasher, 40, [was involved in] online [bickering] with the 17-year-old daughter of a woman Thrasher's ex-husband was dating.... The teen [then] sent a MySpace message to Thrasher, telling her to grow up.

Thrasher ... then created a listing on Craigslist's Casual Encounters section, investigators said. The listing included the teen's picture, employer, e-mail address and cell phone number. Banas said the posting's language would lead people to believe it was an invitation to sexual contact.

Investigators said men called the girl and sent e-mails, text messages and pornography to her cell phone after Thrasher posted the listing....

Now this is bad behavior, and I'd see no First Amendment problem with criminalizing such deliberate lies about particular other people. They are in any event probably civilly actionable as libel or false light invasion of privacy, and there's no constitutional barrier to making them criminal as well. But the statute under which Thrasher is prosecuted isn't limited to false statements; rather, it provides (in relevant part, as revealed by the indictment),

1. A person commits the crime of harassment if he or she: ...

(3) Knowingly ... causes emotional distress to another person by anonymously making ... any electronic communication; or

(4) Knowingly communicates with another person who is ... seventeen years of age or younger and in so doing and without good cause recklessly ... causes emotional distress to such other person; or ...

(6) Without good cause engages in any other act with the purpose to ... cause emotional distress to another person, cause such person to be ... emotionally distressed, and such person's response to the act is one of a person of average sensibilities considering the age of such person.

2. Harassment is a [class D felony if] ...:

(1) Committed by a person twenty-one years of age or older against a person seventeen years of age or younger ...

As I've noted before, this is an extremely vague and potentially broad statute. It's a crime (perhaps a felony) to purposefully "emotionally distress" someone "without good cause," with the jury deciding what's good cause -- imagine how much speech this can cover. Likewise, under subsection 4 (which doesn't seem to be in play in this particular prosecution, though it's not clear from the indictment) it's a crime to even recklessly cause emotional distress to a minor, under subsection 3 to do so knowingly cause emotional distress to anyone by an anonymous electronic communication, whether or not one has "good cause." And consider how broad "emotional distress" can be.

A great deal of speech, including anonymous speech, emotionally distresses people. That doesn't strip it of constitutional protection, and neither should constitutional protection turn to jury conclusions of which causes are good and which are bad.

So it seems to me that the statute is facially overbroad, and thus violates the First Amendment (at least unless a court can somehow interpret the statute narrowly, which is hard for me to imagine given the breadth of its terms, and the absence of any limitation to lies or other unprotected speech). It therefore can't be applied even to someone -- such as Thrasher -- who could indeed be constitutionally punished under a narrower statute.

Thanks to commenter PLR for the pointer.