The Salem witch trials were mostly based on hearsay and public hysteria. In a modern day courtroom, the lawyers must present evidence, that is, facts that can be proven. In addition, motive must be explored not only by the prosecution side but also by the defense side. In other words, a so called witness for the prosecution might be motivated to tell a lie against an alleged perpetrator on trial for his or her own personal motives. These motives are researched by modern day lawyers and presented in court. During the witch trials, the person's social position served as proof alone that their testimony was truthful.
The witch trials were fueled by hysteria. In most cases in modern day court trials, the alleged perpetrators are given a bias free trial. If the media causes a frenzy they move the trial to another area where the defendants can get a fair trial.
Of course history has revealed that the McCarthy Era was a time where a bias free trial was in question because of the overriding powers of the federal government, in terms of interviewing and covert recording of alleged perpetrators' conversations.
In addition, modern day courtrooms have jury members selected in such a way as to be satisfactory to both the defense lawyer and the prosecuting lawyer. Therefore, a jury full of members with similar views of the alleged perpetrators seldom occurs. Juries are usually selected with a variety of people of differing races, religions and attitudes.
During the Salem witch trials, only a few people had the power to choose the fate of an individual. In addition, they usually knew each other and believed in the same religion, attended the same congregation and socialised among the same people. Therefore, there was a lot of pressure for them to act in a way in accordance with their peers.