Sources of law — custom and treaty, legislation, precedent

A dispute reaches a judge and there is no section that covers it. No Act, no rule, nothing on the point. The judge still has to decide — she cannot send the parties away saying the legislature forgot. So where does she get the rule from? Answer that and you have this topic.

In two minutes

Indian law comes from four sources — legislation, precedent, custom and treaty — and they do not carry equal weight: a statute beats a conflicting custom, a Supreme Court precedent binds every court under Article 141, and a treaty needs Parliament's own legislation before an Indian court can enforce it.

Four places a rule can come from

In Topic 1.1 you learned what makes something law. This topic asks the next question: where does it come from before it becomes law? In India the answer is four sources, and they do not carry equal weight.

Legislation is law that somebody sat down and wrote. Precedent is law that emerged from deciding real disputes. Custom is law that nobody made at all — it grew, and the State later recognised it. Treaty is law agreed with other countries, which in India needs a further step before it binds anyone here.

Keep that ordering in your head, because a favourite examiner's trick is to give you a situation where two sources collide and ask which wins.

Legislation — the source that outranks the others

Legislation is the primary source in a modern legal system, and in India it runs in a hierarchy you already met: the Constitution at the top, then Acts of Parliament and the State Legislatures, then the delegated legislation those Acts authorise.

Its advantages are the obvious ones. It is deliberate — debated and voted on rather than discovered. It is prospective — it tells you the rule before you act, where a judgment tells you afterwards. It is comprehensive — it can lay down a whole scheme at once, which a court deciding one dispute cannot.

Its weakness is rigidity. A statute cannot anticipate every situation, and the words chosen in 1872 must be applied to facts nobody imagined then. That gap is exactly where the other sources do their work.

Precedent — and the two words you must get right

When a court decides a case, the rule it applied binds later courts. That is the doctrine of stare decisis — to stand by what has been decided. In India it is not merely a convention; Article 141 of the Constitution states that the law declared by the Supreme Court shall be binding on all courts within the territory of India.

But not every sentence in a judgment is binding, and this is where marks are won. The ratio decidendi is the rule of law on which the decision actually rests — the reasoning without which the case could not have been decided the way it was. Everything else is obiter dicta : observations by the way. Obiter can be quoted and can persuade, especially from a senior judge, but it does not bind.

The practical test is subtraction. Take a proposition out of the judgment. If the outcome would still have been the same, it was obiter. If the case collapses without it, that is your ratio.

A few rules of the hierarchy that examiners like to probe. The Supreme Court binds every court in India but is not bound by itself, so it can depart from its own earlier view. A High Court binds all courts subordinate to it within its own State, but a judgment of one High Court is only persuasive in another. Within a court, a larger Bench binds a smaller one. And a decision given in ignorance of a binding statute or precedent is per incuriam — it has no binding force at all.

Finally, two things a later court can do with an inconvenient precedent. It can overrule it, if it is a higher court, which destroys it. Or it can distinguish it — hold that the material facts are different so the rule does not apply. Distinguishing is the everyday craft of advocacy, and it is what you are really doing when you brief a case in Topic 1.4.

Custom — the oldest source, and the hardest to prove

Long before any legislature existed, communities had rules. Custom is that law: a practice observed for so long that people came to treat it as binding. The Constitution takes it seriously — Article 13(3)(a) says that in Part III, "law" includes any custom or usage having the force of law, which means an unjust custom can be struck down as violating fundamental rights just as a statute can.

But a court will not accept any old practice as law. A valid custom must be ancient , observed for long and without interruption; continuous and uniform ; certain in its terms; reasonable ; obligatory rather than merely optional; and not opposed to public policy or to any statute . That last condition decides every clash: where a statute and a custom conflict, the statute wins.

Custom matters most in personal law, and the statutes say so expressly. Section 3(a) of the Hindu Marriage Act, 1955 defines custom and usage as a rule continuously and uniformly observed for a long time, which has obtained the force of law, provided it is certain and not unreasonable or opposed to public policy.

The party alleging a custom must prove it. It is a question of fact, and vague assertions of "our community has always done this" fail routinely.

Treaty — and why India is dualist

India signs a convention. Does it become law here the moment the signature dries? No. India follows the dualist approach: international law and domestic law are separate systems, and a treaty does not become enforceable in Indian courts by itself. It needs enabling legislation, and Article 253 gives Parliament the power to make any law for the whole or any part of India for implementing a treaty, agreement or convention — including on subjects that are otherwise in the State List.

That is the rule. The interesting part is what courts do in the meantime. Where there is a gap in domestic law and an international obligation India has accepted, the Supreme Court has been willing to fill it. In Vishaka v. State of Rajasthan (1997) there was no statute on sexual harassment at the workplace, so the Court drew on the Convention on the Elimination of All Forms of Discrimination Against Women and laid down binding guidelines until Parliament legislated. Parliament eventually did, in 2013.

So the accurate statement for an answer is this: a treaty is not automatically law in India, but it can be used to interpret domestic law and to fill a vacuum where there is no inconsistent statute.

When they collide

Put the four together and the working order is: a statute displaces an inconsistent custom; a Supreme Court precedent binds every court but yields to a statute that changes the law prospectively; delegated legislation falls if it exceeds its parent Act; and a treaty waits for Parliament unless a court is using it to fill a genuine gap.

If a question gives you a conflict, say which source wins and why — the reason carries the mark, not the conclusion.

Cheat sheet

Legislation
Law made deliberately by a legislature. Prospective and comprehensive, but rigid — it cannot anticipate every future fact.
Precedent
Law that emerges from deciding real disputes and then binds later courts facing the same question.
Stare decisis
"To stand by what has been decided." The doctrine that makes a court follow its own and higher courts' past rulings.
Ratio decidendi
The rule of law a decision actually rests on. This is the part that binds later courts.
Obiter dicta
Observations made along the way that the decision did not depend on. Persuasive, never binding.
Per incuriam
A decision reached in ignorance of a binding statute or precedent. It has no binding force.
Custom
A practice observed so long that people treat it as binding, valid only if it clears six conditions including consistency with statute.
Dualism
India's approach to international law: a treaty is a separate system from domestic law and needs enabling legislation to be enforceable here.
Article 141
Makes the law declared by the Supreme Court binding on every court in India.
Article 253
Gives Parliament power to legislate to implement any treaty, even on a subject otherwise in the State List.

Questions students ask

Why does legislation outrank precedent and custom?
Because it is made by an elected body through a deliberate process, and it can lay down a whole scheme in advance rather than reacting to one dispute at a time. When a later statute conflicts with an existing custom or an earlier judicial rule, the statute prevails — that is the point of Parliament being able to legislate at all.
Can a Bombay High Court judgment bind a court in Chennai?
No. A High Court binds only the courts subordinate to it within its own State. A judgment of one High Court is merely persuasive in another State's courts, which may follow it, disagree with it, or wait for the Supreme Court to settle the point.
What happens when a custom conflicts with a statute?
The statute wins. One of the six conditions for a valid custom is that it must not be opposed to public policy or to any statute, so a custom that clashes with legislation was never a valid custom to begin with — there is no real contest between the two.
Is a treaty automatically law in India once the government signs it?
No. India is a dualist country, so a signed treaty does not bind Indian courts by itself. Article 253 lets Parliament pass a law to implement it, and only that law is enforceable. Courts can still use the treaty's text to interpret an ambiguous statute or, as in Vishaka, to fill a gap where no domestic law exists at all.