I encourage people not to be too positive about the perpetrator's identity until there's some sort of outside confirmation.
UPDATE: Here's a blog post with an apology. The domain shows as registered to the right person, in Tucson Arizona. Nonetheless, on the Internet you can't be entirely sure about identities, something that's worth remembering.
ANOTHER UPDATE: But apparently she's got some blog-stalking history with Bainbridge.
STILL MORE: Michelle Malkin emails that she has confirmed Deb Frisch's identity, and her resignation, with the University of Arizona. (LATER: She's posted the email here).
Eric Scheie observes: "Of all the various forms of viciousness I've seen in the years I've been blogging, this one takes the cake."
And The Anchoress writes: "And to those who are supporting her or trying to keep her words from being read: 'Have you no decency. Finally, have you no decency?' And, her idea that ideological differences has rendered the man and his child “not human,” that is something that should concern all of us."
Sadly, Gateway Pundit reports that threats against children are nothing new.
More thoughts here: "The blogger on blog reader war concerns me. I've seen the blogosphere do wonderful things. Some of the investigative reporting that's been done has been Grade A. But when blogs attack other blogs, or get attacked by blog readers, I become distressed at how quickly the voyeurs give in to the instinct to engage in school playground behavior. The pile-on, hand wringing and 'ah-ha' -ism becomes childish pretty quickly. Personally, I'd like to read less of this. So let's close the book on all this Frisch-ing, and get back to the important things - Iraq, Immigration reform, and those crazy North Koreans."