On Thursday, Cook County Circuit Judge Vincent Gaughan said he would hold in contempt of court anyone who comes inside the courthouse with a sign and starts "waving it around."
Last month, a protester with a sign that made a reference to the 16 times Van Dyke shot McDonald confronted him outside the courthouse.
Vaughn didn't take any further legal action nor suggest that he'd try to stand in the way of protesters carrying signs outside the courthouse. Protesters have gathered there during past McDonald appearances.
Van Dyke is charged with first-degree murder in the 2014 shooting.