You are either completely misunderstanding or misrepresenting the holding in Watts.
The reason the comment about L.B.J was protected was not because the "if X happens" language, but because even crude, hyperbolic political commentary is absolutely protected under US law.
> you can't determine from the specific language people are using that this is definitely not an immediate threat.
"Taken in context, and regarding the expressly conditional nature of the statement and the reaction of the listeners, we do not see how it could be interpreted otherwise."
It is literally right there in the decision, so in fact the conditional language is being considered.
> you can't determine from the specific language people are using that this is definitely not an immediate threat.
That's utterly irrelevant.
How is this utterly irrelevant? it seems to be the substance of the entire legal problem.
1) You keep talking about immediate threats. A true threat does not need to be immediate. You may be conflating this with the related doctrine on incitement. (Basically, speech meant to incite violence is protected unless the violence is imminent. "You should kill the governor this weekend" is basically 100% fine under US law. "You should kill the governor right now" might not be. Yes, US law is weird.)
2) You can't determine from any language that something is definitely not a true threat (or an immediate threat, as you persist on calling it). Language is malleable. My use of the word "malleable" could be a coded reference which means, to those in the know, that you should be hunted down and killed. I mean, it doesn't really sound like it is, but how can you determine that? The answer is that you don't need to. Speech that you "can't determine" isn't a true threat is still protected. It's only when speech rises to the level of being clearly intended to cause fear in the recipient that it might lose its protection. (Which is, incidentally, one of the larger reasons the speech was obviously protected: It wasn't made to the person allegedly being threatened. Comments about a person face a vastly higher bar than comments to a person. If the person who made the woodchipper comment had no reason to think the judge would ever see it, it couldn't have been a true threat.)
In short, the true threats exception is vastly narrower than you seem to think.
The reason the comment about L.B.J was protected was not because the "if X happens" language, but because even crude, hyperbolic political commentary is absolutely protected under US law.
> you can't determine from the specific language people are using that this is definitely not an immediate threat.
That's utterly irrelevant.