The ACLU just sent out this statement from Hina Shamsi, director of the ACLU's National Security Project:
We're deeply skeptical that prosecuting WikiLeaks would be constitutional, or a good idea. The courts have made clear that the First Amendment protects independent third parties who publish classified information. Prosecuting WikiLeaks would be no different from prosecuting the media outlets that also published classified documents. If newspapers could be held criminally liable for publishing leaked information about government practices, we might never have found out about the CIA's secret prisons or the government spying on innocent Americans. Prosecuting publishers of classified information threatens investigative journalism that is necessary to an informed public debate about government conduct, and that is an unthinkable outcome.
A successful prosecution of Wikileaks would mean that the government could wield a credible threat of prosecution against mainstream media organizations under the same law -- which is the same as giving the unconstitutional power of prior restraint over what news organizations publish. Which, as I've said before, is exactly what I think most of the people calling for prosecution want.