Doctrines Glossary

These named doctrines recur across the cases above; knowing the doctrine independent of any one case is often what an exam actually tests.

• Basic Structure Doctrine. Evolved in Kesavananda Bharati (1973): Parliament's power to amend the Constitution under Art. 368 is wide, but it cannot alter the Constitution's "basic structure" or essential features. There is no exhaustive list of what qualifies — the Court has, case by case, held judicial review, federalism, secularism, free and fair elections, separation of powers, the rule of law, and the FR–DPSP balance to be part of it. This is India's most exam-tested doctrine.

• Doctrine of Severability. If part of a statute is unconstitutional and part is valid, courts strike down only the invalid part, provided the valid part can survive independently without altering the law's essential purpose. If the valid and invalid parts are so intertwined that the legislature would not have enacted one without the other, the entire statute falls (as happened with Sec. 66A of the IT Act in Shreya Singhal, which the Court found could not be meaningfully severed and struck down wholesale).

• Doctrine of Eclipse. A pre-Constitution law inconsistent with a Fundamental Right is not automatically void — it is merely rendered dormant ("eclipsed") as against citizens for the period of inconsistency; it revives if the inconsistency is later removed (e.g., by a constitutional amendment) and remains fully operative as against non-citizens throughout. Applies only to pre-existing laws, not laws made after the Constitution, which are void ab initio to the extent of inconsistency.

• Doctrine of Colourable Legislation. Encapsulated as "what cannot be done directly cannot be done indirectly" — a legislature lacking competence over a subject cannot achieve the same result by dressing up the law under a different, permissible head of legislative power. Courts look at the substance and real effect of a law, not its form or stated object.

• Doctrine of Pith and Substance. Used to resolve disputes over legislative competence between the Union and State lists (Seventh Schedule) — a law's "true nature and character" (its pith and substance) is examined; if it substantially falls within the legislature's competence, an incidental encroachment into another list's territory does not make it invalid.

• Doctrine of Harmonious Construction. When two provisions of a statute or the Constitution appear to conflict, courts interpret them so both can operate together as far as possible, rather than treating one as overriding or nullifying the other — used, for instance, in reconciling Fundamental Rights with the Directive Principles of State Policy.

• Public Interest Litigation (PIL) — origins. Traditional locus standi (only a person with a direct, personal legal injury may sue) was relaxed from the late 1970s/early 1980s, primarily through S.P. Gupta (1981) and cases like Bandhua Mukti Morcha (1984) and Hussainara Khatoon (1979) — allowing any public-spirited citizen, lawyer, or organisation to petition on behalf of persons unable to approach the Court themselves (prisoners, bonded labourers, slum dwellers). Courts also began treating informal communications — a postcard or newspaper report — as writ petitions ("epistolary jurisdiction"), radically widening access to constitutional remedies.