Adversarial system

The adversarial system or adversary system is a legal system used in the common law countries. It is a system where two advocates represent their parties' positions before an impartial person or group of people. This is usually a jury or judge who attempt to determine the truth of the case. It is in contrast to the inquisitorial system used in some civil law systems (i.e. those deriving from Roman law or the Napoleonic code). This is where a judge or group of judges opens an official inquiry and decides the case.
The adversarial system is the two-part system under which criminal law courts operate. On one side is the prosecution who usually represents the government. The other side is the defense who represents the defendant. Each party may call witnesses and ask questions. Each party may present evidence based on legal ethics and that is approved by the court. For example, legal ethics prevent a lawyer from calling a witness they know will lie on the witness stand. Justice is served when the most effective adversary is able to convince the jury or judge that his or her case is the correct one.