The inquisitorial system is a legal system where the court is actively involved in determining the facts of the case, as opposed to the adversarial system where the judge's role is that of an impartial referee (except for questions of law) and the prosecution (or plaintiff in civil cases) and defendant plead their case before a jury who determines the facts of the case; though in some adversarial systems it is the judge who is both the trier of fact and law. It is important to note that even in adversarial proceedings in some jurisdictions the judge may participate in the fact finding inquiry by questioning witnesses appearing before her. The rules of admissibility of evidence may also allow the judge to act more like an inquisitor than an impartial arbiter of justice.

The inquisitorial system applies to questions of procedure as opposed to questions of substantial law and is most readily used in many, but not all civil legal systems. However, some jurists do not recognize this dichotomy and see procedure and substantive legal relationships as being interconnected and part of a theory of justice as applied differently in various legal cultures.

A commonly held myth is that inquisitorial systems do not allow for the presumption of innocence. This myth comes in large part because in civil law nations, an investigating magistrate supervises police investigations. However the magistrate does not determine innocence or guilt and functions much as a grand jury does in certain common law nations. In addition, there is some confusion in that, unlike common law nations, most civil law systems have no concept of a guilty plea. A criminal defendant who confesses, has his confession entered into evidence and the trial continues as usual.

In addition, contrary to myth, modern inquisitorial systems also separate the role of the prosecutor and judge in criminal cases and provide a criminal defendant a right to a defense and a right to counsel.

Table of contents
1 History
2 Modern usage in France
3 Inquisitorial tribunals in common law countries
4 Inquisitional courts in international law

History

In the common law legal system historically the adversarial system was used to uncover the positions of litigants and to determine their opposing views regarding their individual entitlements; whereas the inquistiorial system (perhaps best known from the Inquisition) was a system in which the judges or decisionmakers took an active role in uncovering the evidence they needed to justify their decisions. As canon law continued to be applied throughout Europe throughout the middle ages, this inquistorial system of the Catholic church and ecclesiastical courts continued to be the most popular method by which disputes were adjudicated, perhaps as most feudal overlords remained linked to the powers of eclessiastical bodies where Roman law was preserved and learned jurists available for consultation, whereas in England individuals were granted access to various levels of courts without the intervention of the Lord of the Manor and thus the Court system developed independently of the ecclessiastical system.

In the development of modern legal institutions which occurred in the 19th century, for the most part, most jurisdictions did not only codify their private law and criminal law, but the rules of civil procedure were review and codified as well. It was through this movement that the role of an inquisitorial system became enshrined in most European civilian legal systems. However it would be too much of a generalization to state that the civil law is purely inquisitorial and the common law adverarial, indeed the ancient Roman custom of arbitration was the earliest form of adverarial proceeding, has now been adapted in many common law jurisdictions to a more inquisitorial form. In some mixed civil law systems, such as Scotland, Quebec and Louisiana while the substantial law is civilian in nature and evolution, the procedural codes that have developed over the last several hundred years are based upon the English adversarial system.

Modern usage in France

The main feature of the inquisitorial system in France (and other countries functioning along the same lines) in criminal cases is the function of the juge d'instruction. The juge d'instruction is a specially trained judge who conducts the investigations, in the case of severe crimes or complex enquiries. The judge hears witnesses and suspects, orders searchers and delivers warrants. The goal of the juge d'instruction is not the prosecution of a certain person, but the finding of truth, and as such his duty is to look both for incriminating and exculpating evidence (Code of Penal Procedure, article L81). Both the prosecution and the defense may request actions from the judge, and may appeal the judge's decision before the court of appeal.

If the juge d'instruction decides there is a valid case against a certain suspect, he defers the suspect to a tribunal or court, where the proceedings are adversarial, opposing the prosecution and the defense.

In administrative courts such as the Conseil d'État, the proceedings are markedly more inquisitorial: most of the procedure is conducted in writing as opposed to an open court, and the parties are not even required to attend the court appearance. This reflects the fact that administrative lawsuits are for the most part about matters of formal procedure and technicalities.

Inquisitorial tribunals in common law countries

Administrative proceedings in many common law jurisdictions are similar to their civil law counterparts, they are also conducted on a more inquisitorial model. A good example are the many administrative boards such as the New York City Traffic Violations Bureau, a minor tribunal that deals with traffic infractions where the adjudicator also functions as the prosecutor and questions the witnesses. He or she also renders judgment and sets the fine to be paid. These types of tribunals or boards can be found in most modern democracies. They function as an expedited form of justice where the state agents conduct an initial investigation and the adjudicator's job is to confirm these preliminary findings through a simplified form of procedure that grants some basic amount of due process or fundamental justice in which the accused party has an opportunity (usually futile) to place his or her objections on the record.

Inquisitional courts in international law

International tribunals intended to try crimes against humanity, such as the Nuremberg Trials and the International Criminal Court have used the inquisitiorial system rather than the adversary system.