This paper explores twelve foundational doctrines of international law, each playing a crucial role in shaping the global legal order. These doctrines—including sovereignty, non-intervention, recognition, and universal jurisdiction—balance the principles of state autonomy with the need for international cooperation and justice. By examining landmark case laws, such as ‘The Island of Palmas’ and ‘Nicaragua v. United States’, the paper illustrates how these doctrines are applied in practice. This analysis provides insight into the complex interplay between national interests and global governance, highlighting the evolving nature of international law.