Since there's a lot of incendiary rhetoric about killing people being thrown around, let's review the First Amendment status of it, shall we?

There are two relevant First Amendment exceptions: true threats and incitement.

This is necessarily a bit simplified.

/1

/2 First, "true threats." A true threat is a threat that a reasonable person would interpret as a sincere expression of intent to do harm. It must be uttered with some culpable level of intent -- either intent that it be taken as true, or recklessness about how it's taken.

/3 Then there's incitement. Incitement is outside the First Amendment when it's intended, and likely, to cause imminent lawless action.

That's it. Those are the only two plausible exceptions for the current fad "we should kill all of party X" or "this guy should be executed."

/4 What about hate speech, you might ask?

There is no hate speech exception to the First Amendment. "Hate speech is not free speech" is an aspirational slogan and not an accurate statement of the law. This is not a matter of genuine legal controversy.

/5 What about fighting words, you might ask?

If the fighting words doctrine still exists, it is limited to face-to-face insults likely to provoke an immediate violent response from the target.

/6 Much of this rhetoric is extremely morally blameworthy, of course, and the First Amendment doesn't protect people from the social consequences that should flow from using it.
/end