The two systems in question, the Adversarial System and the Inquisitorial System have two different points of view on how a trial should be conducted. In the Adversarial System, the prosecutor and the defense counsel engage to prove that their side should win the trial. The judge and the jury are selected to ensure that the trial is conducted lawfully, and to determine the winner. Here, both sides argue their case. The verdict is then given jury, and the sentence is given by the jury or the judge.
In the Inquisitorial System, judges play the role of an investigator. Here, the accused is not under oath. Witnesses are called in and questioned by the judge. Attorneys can only question the witnesses only if the court allows. The court announces the verdict and sentence.
In the Adversarial System, the role of the fact finder is played by the attorneys. The prosecutor and the defense counsel are responsible for finding all the information that is relevant to the case and using it to strengthen their argument so that they can win. In the Inquisitorial System, the role of fact finding is left to the judge. He is responsible for interviewing the accused and the witnesses. In some cases, the accused will have been questioned by other parties such as police or an examining magistrate.
Of the two models, the Crime Control Model and the Due Process Model, the one that best fits the inquisitorial system is the Crime Control Model. This model prioritizes control of crime. The main purpose of this model is to find out the truth. This is done by the questions that are advanced to the accused by various persons, including judges.
The model that fits the adversarial system is the Due Process Model. This model gives everybody a fair chance of representation and presumes the accused innocent until proven guilty. A fair trial is hence the essence of the Due Process Model.