Orin Kerr writes:
In an earlier post, co-blogger David Post pointed to a state trial court rulingin Montana, for which he was an expert for the defense, which concluded that the government needs a warrant under the Fourth Amendment and/or the Montana Constitution for a police officer to go undercover on Facebook as a teenage girl, “friend” a target, and have conversations with that target. Here’s a different perspective on the case. To the extent the judge was relying on the Montana Constitution, the decision is plausible. On the other hand, the decision is plainly wrong if it was relying on the federal Fourth Amendment.
Read more on WaPo The Volokh Conspiracy.