A written constitution typically includes its own procedure for amendment, allowing the document to be updated over time without requiring an entirely new constitution to be drafted from scratch. The doctrine of basic structure addresses a question that arises once such an amending power exists: is that power genuinely unlimited, capable of changing absolutely anything in the constitution, including the very provisions that establish democracy, judicial independence, or fundamental rights themselves -- or does the amending power itself have implicit limits?

The doctrine holds that the power to amend a constitution, however broadly worded, does not include the power to destroy or fundamentally alter the constitution's own basic or essential structure -- the core features that give the document its identity as a constitution in the first place, rather than a document that could, through its own amending procedure, be used to dismantle itself entirely. An amendment that alters even a specifically named article using the correct, prescribed amending procedure may nonetheless be struck down if, in substance, it damages or destroys an essential feature of the basic structure, since following the correct procedure does not, by itself, validate an amendment that exceeds the amending power's own inherent limits.

The doctrine does not freeze the constitution in its original form or prevent legitimate amendment altogether; ordinary amendments, even significant ones, remain valid provided they do not damage or destroy an essential feature of the basic structure. Courts applying the doctrine examine the substance and effect of an amendment, not merely its form or the procedural correctness of its passage, asking whether the amendment, if allowed to stand, would fundamentally alter the identity of the constitution itself.

Because the doctrine limits the amending power rather than the ordinary legislative power to pass laws, it applies specifically to constitutional amendments and does not restrict a legislature's ordinary power to pass or repeal statutes within its existing constitutional authority.