From the same mindset:
There was a 1995 Supreme Court case, McIntyre v. Ohio Elections Commission
. It involved a plaintiff (McIntyre) that was fined $100 for distributing political fliers that were anonymously written. The court ruled 7-2 in favor of McIntyre. In that ruling, Stevens, writing for the majority said:
Under our Constitution, anonymous pamphleteering is not a pernicious, fraudulent practice, but an honorable tradition of advocacy and of dissent. Anonymity is a shield from the tyranny of the majority. ... It thus exemplifies the purpose behind the Bill of Rights, and of the First Amendment in particular: to protect unpopular individuals from retaliation--and their ideas from suppression--at the hand of an intolerant society. The right to remain anonymous may be abused when it shields fraudulent conduct. But political speech by its nature will sometimes have unpalatable consequences, and, in general, our society accords greater weight to the value of free speech than to the dangers of its misuse.
Two justices dissented, Rehnquist and Scalia.
In the late 1980's Ed Whelan was a clerk for Scalia. This weekend he outed a pseudonymous blogger. How about that?