In Miller's dramatization of the events that occurred in the Salem Witch trials, John Proctor's actions did indeed have an impact on the townspeople turning on the courts, which eventually led to the chaos dying down and ending. Before John Proctor, Elizabeth Proctor, Martha Corey and Rebecca Nurse were arrested, the people that had been accused and imprisoned were the degenerates of the town of Salem. They were the drunks, the no-goods, the heretics and the homeless. However, the Proctors, Coreys and Nurses were upstanding and well-respected members of the town. Their arrests were a bit harder to swallow; it was much harder to believe that they could be witches. The townspeople didn't like it, and started to question the authority of the courts.
The day that John is scheduled to hang, Parris is worried that if they do, the people of the town will revolt against the courts, overthrow them, and perhaps enact violence against himself and the judges. He says of Proctor, "it were another sort that hanged till now," and that "you cannot hang this sort. There is danger for me." What he means by this is that John is the sort of man that people respected and admired, and the town won't stand for him dying. He's worried that if they do, the people will revolt. They already are to a certain extent.
Proctor stood up to the courts, defying them with his honesty and integrity, and his valiant efforts to prove them wrong. In a statement against the courts, "there were hardly thirty people that come to hear" John's excommunication trial. That speaks volumes, that no one showed up at John's excommunication; it indicates that his valiant example had a strong impact on their attitudes and beliefs about the validity of the courts and their rulings.
I hope that those thoughts helped; good luck!