Material threats, the ones that seem actionable, seems like a good line to draw, and I think it's the current state of the law in the U.S. E.g., if I threaten

Material threats, the ones that seem actionable, seems like a good line to draw, and I think it's the current state of the law in the U.S. E.g., if I threaten to "kill you" because of a bad book review, I'm allowed to say that. But if I threaten to "kill you in your living room tomorrow night at 7pm", that's illegal, because I've provided specific detail about when/where. Honestly I don't know the specifics of the US law, if someone else could chime in and clear things up a bit, that'd probably be better than me butchering the law.