The Preamble provided the basic philosophy and fundamental values to the Indian constitution. It contains the ideals, objectives and basic principles of the Constitution. The salient features of the Constitution have evolved from the objectives enshrined in the Preamble.
In berubari union case the SC stated that Preamble is key to the makers of the constitution. But SC held that Preamble is not part of the constitution. But later on in SC Judgements it was held that preamble is part of the Indian constitution.
In the Kesavananda Bharati case (1973) the Supreme Court reversed its earlier stand and held that the Preamble is a part of the Constitution. It observed that the Constitution should be read and interpreted in the light of the grand and noble vision expressed in the Preamble.
In the LIC of India case (1995), the Supreme Court again held that the Preamble is an integral part of the Constitution. However, it is not enforceable in a court of law. It can be amended like any other part of the constitution; however, the amendment should not violate the doctrine of basic structure.
Thus, the constitution is an integral part of the constitution. The ideals enshrined in the Preamble helps the judiciary in unravelling the minds of the founding fathers in case of any difficulty in interpreting the provisions of the constitution.