Internal Security is a fundamental concept in Indian polity, defined as the protection of the country from threats originating within its borders to ensure the safety of citizens and the stability of the state. It is distinct from external security, which is concerned with foreign aggression. The Ministry of Home Affairs (MHA) serves as the central nodal agency responsible for this domain.
The concept's origin is ancient, with references in Kautilya's Arthashastra (3rd century BCE) categorizing threats to the state. In the modern context, the Union's responsibility is mandated by Article 355 of the Constitution, which requires it to protect every State against internal disturbance. This framework addresses major problems like terrorism, Left-Wing Extremism (LWE), and communal violence.
The mechanism relies on a legislative framework and specialized institutions. Key acts include the Unlawful Activities (Prevention) Act (UAPA) (1967), which targets terrorism, and the National Security Act (NSA) (1980), which allows for preventive detention for up to twelve months. The constitutional basis for preventive detention is found in Article 22(3)(b). Related institutions include the National Investigation Agency (NIA), established under the NIA Act of 2008, which investigates terror-related crimes.
The internal security framework has undergone significant recent changes. The Unlawful Activities (Prevention) Amendment Act, 2019, strengthened anti-terror laws by allowing the designation of individuals as terrorists. A major reform came in July 2024 with the replacement of colonial-era criminal laws. The Indian Penal Code was replaced by the Bharatiya Nyaya Sanhita (BNS), the Code of Criminal Procedure by the Bharatiya Nagarik Suraksha Sanhita (BNSS), and the Indian Evidence Act by the Bharatiya Sakshya Adhiniyam (BSA). Notably, the BNS repealed the outdated law on sedition.