A federal judge ruled on Thursday that prosecuting a man for writing harassing tweets directed at a prominent Buddhist religious leader violated the tweeter's First Amendment rights.

The target of the harassment, Alyce Zeoli, is "an enthroned tulku or reincarnate master who was enthroned in 1988 as a reincarnate llama." The defendant, William Cassidy, became involved with Zeoli and her religious sect in 2007, but they eventually had a falling-out. Cassidy evidently became embittered, and in 2010 he began a campaign of harassment against Zeoli on Twitter and on a blog hosted by Blogspot.

The tweets ranged from the merely vulgar ("that ho bitch so fat if she falls & breaks her leg gravy will spill out") to arguably threatening ("want it to all be over soon sweetie?"). The federal government found the messages sufficiently disturbing to indict Cassidy for violating a 2006 anti-stalking law that prohibits the use of an "interactive computer service" to cause "substantial emotional distress." The government claimed that Zeoli "feared for her safety," and "has not left her house for a year and a half, except to see her psychiatrist."

Cassidy argued his prosecution violated the First Amendment. And in a Thursday ruling, Judge Roger W. Titus agreed.

Titus begins his analysis of the case with an explanation of how Twitter and blogs work, which we can't resist blockquoting:

Because this case involves First Amendment issues, terms that were in use by citizens when the Bill of Rights was drafted may help in understanding the legal context of Blogs and Twitter. Suppose that a Colonist erects a bulletin board in the front yard of his home to post announcements that might be of interest to others and other Colonists do the same. A Blog is like a bulletin board, except that it is erected in cyberspace rather than in one’s front yard. If one Colonist wants to see what is on another’s bulletin board, he would need to walk over to his neighbor’s yard and look at what is posted, or hire someone else to do so. Now, one can inspect a neighbor’s Blog by simply turning on a computer. Twitter allows the bulletin board system to function so that what is posted on Colonist No. 1's bulletin board is automatically posted on Colonist No. 2's bulletin board for Colonist No. 2 to see. The automatic postings from one Colonist to another can be turned on or off by the owners of the bulletin boards, but there is no mandatory aspect of postings on one Colonist's bulletin board showing up on the other's. It is entirely up to the two Colonists whether their bulletin boards will be interconnected in such a manner.

"Twitter and Blogs are today's equivalent of a bulletin board that one is free to disregard, in contrast, for example, to e-mails or phone calls directed to a victim," Titus writes. Because Zeoli was free not to look at, or subscribe to, the messages on Cassidy's "bulletin board," the government's regulation of Cassidy's speech does not serve a compelling state interest.

Judge Titus also holds that Zeoli is a prominent religious leader, and that at least some of Cassidy's tweets were criticisms of Zeoli's religious beliefs and qualifications to lead her sect. Such speech, Titus holds, is at the core of what the First Amendment protects.

The ruling was hailed by the Electronic Frontier Foundation, which had filed an amicus brief in the case. "Law enforcement may have disagreed with the tone and content of Mr. Cassidy's speech," said EFF's Hanni Fakhoury, "but the police hauling a Twitter user to jail for offending a public figure was the greater harm."