United States v. Kelner (2d Cir. 1976) 534 F.2d 1020, affirmed a conviction for causing to be transmitted in interstate commerce a communication threatening to injure the person of another (18 U.S.C. 875(c)). Kelner considered those circumstances under which an unequivocal threat that has not ripened into an overt act in the nature of an attempt (i.e., an attempt to carry out the threatened action, not the threat itself) is punishable under the First Amendment even though it may also involve elements of expression. (Kelner, supra, 534 F.2d at p. 1026.) Kelner found that, there was a strong "governmental interest of reducing the climate of violence, to which true threats of injury to others necessarily contribute." (Kelner, supra, 534 F.2d at p. 1026.) The Kelner court explained that Watts found only true threats punishable, and excluded threats which, in context, were conditional and made in jest. (Kelner, supra, 534 F.2d at p. 1026.) Kelner decided that punishable threats were "only those which according to their language and context conveyed a gravity of purpose and likelihood of execution so as to constitute speech beyond the pale of protected 'vehement, caustic . . . unpleasantly sharp attacks on government and public officials.'" (Kelner, supra, 534 F.2d at p. 1026, quoting New York Times v. Sullivan (1964) 376 U.S. 254, 270; see Watts, supra, 394 U.S. at p. 708.) Kelner continued: "The purpose and effect of the Watts constitutionallylimited definition of the term 'threat' is to insure that only unequivocal, unconditional and specific expressions of intention immediately to inflict injury may be punished," in short, those of the same nature as threats properly punished under statutes prohibiting extortion, blackmail and assault notwithstanding the First Amendment. (Kelner, supra, 534 F.2d at p. 1027.)