Sukarno is known not only as the proclaimer of Indonesia and the originator of Pancasila but also as a national figure who introduced the ideas of NKRI and Bhinneka Tunggal Ika into the Indonesian state system. This study aims to examine the essence and existence of both ideas philosophically and then analyze their relationship, and based on that analysis, predict the future of NKRI: Will Indonesia remain with the unitary ideology (NKRI), or could it change to federalism (RIS State)? By using a philosophical research methodology, this study found: First, although NKRI concerns the form of the state and Bhinneka Tunggal Ika as the motto of the Indonesian State, their essence is the same, namely regarding the political ideology of a modern state: "unity in diversity." With this philosophical ideology, Indonesia, which has a diversity of tribes, customs, languages, and religions, has existed since its founding. Second, the NKRI (unitarism) and the RIS State (federalism) have different constitutional bases. The NKRI is based on the 1945 Constitution, while the RIS State is based on the 1949 RIS Constitution, but their philosophical basis is the same, namely Bhinneka Tunggal Ika. Therefore, in the future, Indonesia can remain a Unitary State and become a Federal State. However, although the form of the Unitary State can change to a Federal State in the future, Bhinneka Tunggal Ika remains valid. This is Sukarno's contribution to the State of Indonesia, past, present, and future.