Yeah. Here in California, blackmail is found in the penal code, meaning it's a crime, but the courts allow private parties to use that statute as the basis for a civil claim.

So when I threaten to bring an action based on it, I have to word it very carefully so as to not commit blackmail myself. Usually sometime like.... "Penal code ss 518 and 519 provide that.... courts have held that violations thereof are civilly actionable."

Without the second part, it could appear like I'm threatening to report the opposing party to the police if they don't meet whatever demands I make.