In an important opinion on first amendment rights of lawyers, the United States Court of Appeals for the Sixth Circuit has ruled that the Kentucky State Bar violated and attorney's rights when it sent the attorney a warning letter after he criticized the state Legislative Ethics Commission. The case is called Berry v. Schmitt and it is available here.
The case is important because it discusses the fine line between the authority of the state to regulate attorney speech and the individual attorney's right to express his opinion about judges and the court system. For a number of reasons, attorneys have less freedom of speech than other professionals - there are rules that limit what can be said about on going cases for example - but just as there is a limit to what attorney's can say, there has to be a limit to the power of the state to regulate speech.
For a good discussion of the ruling in Berry go here, here and here.