In Indiana, an employee can threaten to blow his supervisor's head off and the state court can't do anything about it. At least that's what happened in this case, where the threat was deemed to have arisen from a "labor dispute" with his employer.
The employer in this situation entered an injunction against the employee under Indiana's Workforce Violence Restraining Orders Act (WVROA) after the employee's therapist said that he was talking about blowing the supervisor's head off. This comment was made after conversations between the employer and employee where the employee indicated that he disagreed with his work assignment, hours and complained of another employee's preferential treatment.
The Indiana Court of Appeals vacated the injunction, as the WVROA states that it does not apply to cases "involving or growing out of a labor dispute".
To read more about this case, check out this article.