Courts can use the Preamble to strike down a constitutional amendment if it violates the basic structure, even if the amendment procedure under Article 368 was followed.

Preamble and basic structure doctrine: (a) Kesavananda Bharati (1973): Preamble contains basic features (sovereignty, democracy, secularism, federalism, etc.), (b) Parliament can amend Constitution under Article 368, but cannot alter basic structure, (c) If amendment violates Preamble's core values (e.g., removing democracy, secularism), courts can strike it down despite procedural compliance. Preamble thus serves as substantive limit on amending power, not just interpretive aid.