The concept of India is fundamentally defined by its constitutional identity as a sovereign nation-state, formally known as the Republic of India. It is a political and legal concept, established as a Sovereign Socialist Secular Democratic Republic.
The origin of the modern state of India began when it became an independent sovereign state on August 15, 1947, following the partition of British India. The problem it solved was the transition from a British Dominion, governed by the modified colonial Government of India Act 1935, to a fully self-governing republic. The Constitution of India was adopted by the Constituent Assembly on November 26, 1949, and came into effect on January 26, 1950, replacing the 1935 Act as the supreme governing document.
The core mechanism is laid out in Part I of the Constitution, titled "The Union and Its territories". Article 1 is the key provision, stating: "India, that is Bharat, shall be a Union of States". This article establishes the nation's dual name and its federal structure, with the territory comprising the territories of the States, the Union territories specified in the First Schedule, and any acquired territories. The Constitution, which originally contained 395 Articles in 22 Parts and 8 Schedules, establishes a parliamentary system of government based on the Westminster model.
The concept of India connects directly to the Constitution of India, 1950, which is the supreme law. It is intrinsically linked to the principle of the Rule of Law, which is reflected in provisions like Article 14, guaranteeing equality before the law. A significant recent change occurred with the 42nd Amendment Act in 1976, which added the words "Socialist and Secular" to the Preamble, defining the nature of the Republic. The fundamental structure as a Union of States under Article 1 has remained the same since its enactment.