What the courts have found is that in order for a threat to -- for speech, for words alone to constitute a threat, this is from United States v. Kelner, which is a second circuit case, that the threat:

"on its face and in the circumstances which it is made is so unequivocal, unconditional, immediate and specific as to the person threatened as to convey a gravity of purpose, imminent prospect of execution."

-- Barry Steinhardt, in his opening statement to the MTTLR Jake Baker debate.