War has always been a fundamental part in the creation and development of both States and societies. International Law has responded to the needs of limitation of war by creating a legal framework that regulates the authorized use of force, as well as the protection of the common goods, both of combatant and non combatant. However, the “new wars” generate new challenges and realities that have to be analyzed, not only by International Law, but by the social sciences as a whole, which is the only way to achieve “international peace and security”, foundlings of contemporary International Law.