The Indian Constitution, a supreme and living document, guarantees fundamental rights to its citizens. However, laws enacted prior to or after its commencement might contravene these fundamental rights. To address such inconsistencies, the judiciary has evolved several doctrines, one of the most significant being the Doctrine of Eclipse. This doctrine posits that a law violating fundamental rights is not void ab initio (from the beginning) but remains dormant or in a state of eclipse. It can be revived if the conflicting fundamental right is amended or repealed.

The genesis of this doctrine can be traced back to the landmark case of Keshavan Madhava Menon v. The State of Bombay (1951). In this case, a pre-constitutional law conflicted with Article 13(1) of the Constitution, which declares that all pre-existing laws inconsistent with fundamental rights shall be void to the extent of such inconsistency.The Supreme Court held that the pre-constitutional law was not entirely void but became inoperative to the extent of its inconsistency with the fundamental rights. It remained on the statute book, capable of revival if the inconsistency were removed. The fundamental right cast a shadow or an "eclipse" over the inconsistent part of the law.

The doctrine was further elucidated in Bhikaji Narain Dhakras v. The State of MadhyaPradesh (1955). Here, a pre-constitutional law nationalizing motor transport was challenged as violating the fundamental rights of citizens to carry on trade or business under Article 19(1)(g). The Supreme Court reiterated the principle laid down in Keshavan Madhava Menon, stating that the pre-existing law was not wiped out but merely rendered unenforceable against citizens whose fundamental rights were violated. However, it remained operative against non-citizens who were not entitled to these fundamental rights. When Article 19 was subsequently amended, removing the inconsistency, the "eclipse" was lifted, and the law became fully operative even against citizens.

The application of the Doctrine of Eclipse is primarily limited to pre-constitutional laws thatviolate fundamental rights. The rationale is that these laws were valid when enacted, and the Constitution merely rendered them unenforceable to the extent of the conflict.

However, the situation is different for post-constitutional laws that violate fundamental rights. In the case of Deep Chand v. State of Uttar Pradesh (1959), the Supreme Court held that a post-constitutional law made in contravention of fundamental rights is stillborn and void ab initio. It cannot be revived by any subsequent amendment to the Constitution. The legislature lacks the competence to enact a law that infringes upon fundamental rights, and such a law is void from its inception. The Doctrine of Eclipse does not apply to such laws because there is no existing valid law to be eclipsed.

Despite this clear distinction, there have been instances where the application seemed nuanced. In Mahendra Lal Jaini v. The State of Uttar Pradesh (1963), the court clarified that the principle laid down in Deep Chand regarding the inapplicability of the doctrine to post-constitutional laws remains valid. Any ambiguity arose from the specific facts and context of earlier cases.

In summary the Doctrine of Eclipse is a significant tool used by the Indian judiciary to deal with pre-constitutional laws that are inconsistent with fundamental rights. It allows such laws to remain on the statute book, albeit in a dormant state, capable of revival upon the removal of the inconsistency. However, this doctrine does not extend to post-constitutional laws that violate fundamental rights, which are considered void from their inception. The distinction ensures the supremacy of fundamental rights while also giving due consideration to the legislative history of pre-existing laws.