Meaning
Res Judicata is a legal maxim of Latin origin which means the thing has been judged.

Legal Doctrine

The doctrine of Res Judicata is based on three maxims:

1. Nemo debet lis vaxari pro eadem causa (no man should be vexed twice for the same cause).
2. Interest republicae ut sit finis litium (it is in the interest of the state that there should be an end to litigation).
3. Re judicata pro veritate occipitur (a judicial decision must be accepted as correct).

In India, the doctrine of Res Judicata is enshrined in Section 11 of Code of Civil Procedure, 1908:
No Court shall try any suit or issue in which the matter directly and substantially in issue has been directly and substantially in issue in a former suit between the same parties, or between parties under whom they or any of them claim, litigating under the same title, in a Court competent to try such subsequent suit or the suit in which such issue has been subsequently raised, and has been heard and finally decided by such Court.

Nature
In CORPUS JURIS (vol. 34, p.743), it has been stated: Res Judicata is a rule of universal law pervading every well-regulated system of jurisprudence and is put upon two grounds, embodied in various maxims of the common law: the one, public policy, and necessity, which makes it to the interest of the state that there should be an end to litigation: the other, the hardship to the individual that he should not be vexed twice for the same cause.

The principle of res judicata is based on public policy.

What are the essentials of Res Judicata?

It is not every matter decided in a suit that will operate as Res Judicata in a subsequent suit. To constitute a matter as res judicata following conditions must be satisfied:

• The matter directly and substantially in issue in the subsequent suit. Or issue must be the same matter which was directly and substantially in issue either actually in the former suit.
• The former suit must have been a suit between the same parties. Or between parties under whom they or any of them claim.
• Such parties must have been litigating under the same title in the former suit.
• The court which decided the former suit must be competent to try the subsequent suit. Or the suit in which such issue is subsequently raised.
• The matter directly and substantially in issue in the subsequent suit must have been heard and finally decided by the court in the former suit.

Scope of Res Judicata

The sphere of res judicata as enshrined in Section 11 of CPC is not exhaustive, it is ever-growing. The general doctrine is founded on considerations of high public policy. It aims to achieve two objectives, namely, that there must be a finality to litigation, and that individuals should not be harassed twice over with the same kind of litigation.

This is well-settled that in order to decide the question whether a subsequent proceeding is barred by res judicata, it is necessary to examine the question with reference to the (i) forum or the competence of the court, (ii) parties and their representatives, (iii) matters in issue, (iv) the final decision.

It enacts the rule of conclusiveness of judgements as to the points decided, in every subsequent suit between the same parties. The doctrine of res judicata means an issue attaining finality, will not be allowed to be re-agitated.

The principle of res judicata does not apply to bar appeal.

Res judicata and Public Interest Litigation

Even in a PIL, procedural law is applicable though not strictly. Hence, the principle of res judicata is also applicable. Where the prior PIL relates to illegal mining, subsequent PIL to protect the environment is not barred.

Writ Petitions and Res judicata

In M.S.M Shree Krishna, 1960, the Supreme Court held that the general principle of res judicata applies even to a writ petition filed under Article 32 of the Constitution of India. Thus, once the petition is filed under Article 32 by the court, the subsequent petition is barred.

Similarly, a writ petition filed by a party under Article 226 is considered on merit as a contested matter and is dismissed. The decision thus pronounced would continue to bind unless it is otherwise modified or reversed in appeal or in other appropriate proceedings.

The distinction between res judicata and estoppel

Res Judicata is sometimes treated as part of the doctrine of estoppel, but the two are essentially different. Res judicata is the result of a decision of a court of law, whereas estoppel is the result of the act of parties.

The object of the rule of res judicata is to bring an end to the litigation. Whereas the object of the rule of estoppel is to prevent a person who by his conduct induced another to alter his position to his disadvantage.

The jurisdiction of the court is ousted by res judicata, whereas estoppel is only a rule of evidence. The plea of res judicata presupposes the truth of the decision in the former suit whereas the rule of estoppel simply prevents a person from denying what he has once called the truth.

When is the plea of res judicata not applicable?

The Supreme Court has set down 3 exceptions to the rule of Res Judicata.

• The judgment is passed without jurisdiction.
• The matter includes an unadulterated question of law.
• The judgement obtained in the court was by fraudulent means.

What happens in case of an erroneous decision?

Even an erroneous decision on a question of law operates as res judicata between the parties to it. The correctness or otherwise of a judicial decision has no bearing upon the question whether or not it operates as res judicata. A decision in the previous execution case between the parties that the matter was not within the competence of the executing court even though erroneous, is binding on the parties.

Conclusion
The principle of res judicata is an important element of the Indian legal system. It is even applicable to most other jurisdictions of the world. It essentially determines the finality of a suit. The principle is not only restricted to civil courts. But is also applicable to the administrative law and other legislations in India.