a principle of civil procedure according to which the parties in civil proceedings freely dispose of their material and procedural rights.

In Soviet civil procedure the principle of optionality is established by the 1961 Fundamental Principles of Civil Procedure of the USSR and Union Republics. For example, Article 24 establishes the right of the plaintiff to change the basis or object of the suit, to increase or decrease the amount of the actionable claims, or to renounce the suit. The Fundamental Principles of Civil Procedure give any interested person the right to turn to the court for the protection of a violated or disputed right or an interest protected by law. They also establish the obligation of the court to undertake a review of the civil case following such an application. At the same time there are certain limits to the principle of optionality in order to prevent unfavorable consequences that could arise owing to the parties’ lack of legal information or to other factors. Optionality is therefore combined with the obligation of the procuracy and certain other agencies to protect the rights and legal interests of citizens and with the active role of the court. For example, the court is obligated to take all measures provided by law—not limiting itself to the materials and explanations submitted to it—-in order to thoroughly, completely, and objectively clarify the circumstances of the case and the rights and duties of the parties, to explain to the participants in the case their rights and duties, and to warn them of the consequences of procedural actions.

The principle of optionality is also operative to a certain extent in criminal procedure. For example, according to Soviet law, so-called private and private-public complaint proceedings are generally instituted only on the complaint of the victim, and private complaint cases may be stopped when the victim and the accused are reconciled.

The principle of optionality is one of the most important in the civil procedure of the socialist countries. This principle has also been declared in the legislation of most bourgeois states.