You are correct. I'm still confused about their role in the plame leak. Are they defense team?
According to her website bio, Toensing was "instrumental in winning passage" of the 1982 Intelligence Identities Protection Act, under which the intentional disclosure of a covert agent's identity is illegal; she also claimed in a January 12 Washington Post op-ed that she was among those "who drafted and negotiated the scope of" the act.
I am not aware that they are part of Libby's defense team, it may be that they are just outraged how the law they helped write was used for such political purposes.