Old and established legal principles are called legal doctrines. As a general rule, there is an agreement that the doctrine is “a source of inspiration” of the rule of law or a de facto authority. This paper attempts to highlight some leading judgments of the Supreme Court of India to trace the principles of law forming the basis for the application of the doctrines, viz., the doctrines of Pith and Substance, Repugnancy and Colorable Legislation which have been applied by the common law systems. The trident testing the constitutionality of the laws dealing with the legislative relations of the Union and the States in India is analyzed. The author discusses the division of power among the Union and States in the Federal setup of India to decide the constitutionality of the legislations by the Constitutional Courts in India with the tools of interpretative doctrines.

The word ‘doctrine’ has been derived from the Greek word “doxa.” It is understood as “opinion”. Originally, doctrines were those of the Catholic Church. The teachings of the so-called doctors (religious scholars) of the Church were considered as doctrines. But today a doctrine can come from many other sources. Old and established legal principles are called legal doctrines. As a general rule, there is an agreement that the doctrine is not a formal source of law but rather “a source of inspiration” of the rule of law or a de facto authority.1 The paper attempts to highlight some leading judgments of the Supreme Court of India to trace the principles of law forming basis for the application of the doctrines, viz., the doctrines of pith and substance, repugnancy and colorable legislation which have been applied by the common law systems. The trident testing the constitutionality of the laws dealing with the legislative relations of the Union and the States in India is being analyzed in this paper.

Law Review Journal,legal doctrines, Source of inspiration, Repugnancy and Colorable Legislation