People say things on social media that they would not say anywhere else. In this case, a public school teacher was on Words with Friends with someone he didn't know personally. A firearms collector, the teacher made some delusional and conspiratorial comments about space aliens, government control over the weather, government mind control, the Sandy Hook "hoax" and the coming civil war in America. He also said he wanted to kill people. Deeming him incompetent because of mental illness, the school district fired him after he went to a psychiatric hospital. He sues the district under the First Amendment.
The case is Heller v. Bedford Central School District, a summary order decided on November 4. While political candidates can say what they want, public employees cannot. Teachers can speak on matters of public concern, and Heller's comments technically fall within that protection because they addressed current events. But the analysis does not stop there. Most of the time, the courts decide if the school district satisfies the Pickering test, which says that public employees can be fired for addressing matters of public concern if officials reasonably think the speech would disrupt governmental operations. In this case, however, the Second Circuit (Jacobs, Livingston and Rakoff [D.J.]) factors in the "true threat" doctrine in deciding whether the Pickering defense attaches.
Without deciding whether the "true threat" principle applies here, the Second Circuit says "the record is clear that 'an ordinary, reasonable recipient who is familiar with the context of the communication' could well have viewed Heller's communications as 'a threat of injury.'"
Heller sought a trial in this case, arguing that his comments were "off-the-cuff social media banter" that included humor. But the Court of Appeals thinks Heller's comments were made in earnest, "and his conduct raised prudent concern about the risk of a school shooting."
I s'ppose cases like this will become more prevalent in the future. Social media is the Wild West of free speech, and the 2016 Presidential campaign saw a major party candidate joke about having his opponent assassinated. But anything goes in politics. Anything does not always go when you work for the government.