Offences against the State are concerned with the protection of India’s sovereignty, unity, integrity and national security. The Bharatiya Nyaya Sanhita, 2023 (BNS) retains a separate chapter on such offences, with Section 152 specifically addressing acts endangering the sovereignty, unity and integrity of India. This article examines the scope and legal implications of Section 152, particularly its application to secession, armed rebellion, subversive activities and separatist activities. It also examines the relationship between Section 152 and the fundamental right to freedom of speech and expression under Article 19(1)(a) of the Constitution. The judicial principles laid down in Kedar Nath Singh v. State of Bihar, Balwant Singh v. State of Punjab and Vinod Dua v. Union of India are analysed to determine the constitutional limits of offences affecting State security. The Mohd. Ajmal Amir Kasab v. State of Maharashtra case is discussed as a comparative illustration of serious threats to national security. The article argues that Section 152 must be interpreted carefully to protect the State from genuine threats while preserving legitimate democratic criticism and dissent.