Collective security can be understood as a security arrangement, political, regional, or global, in which each state in the system accepts that the security of one is the concern of all, and therefore commits to a collective response to threats to, and breaches of peace. Collective security is more ambitious than systems of alliance security or collective defense in that it seeks to encompass the totality of states within a region or indeed globally, and to address a wide range of possible threats. While collective security is an idea with a long history, its implementation in practice has proved problematic. Several prerequisites have to be met for it to have a chance of working. It is the theory or practice of states pledging to defend one another in order to deter aggression or to target a transgressor if international order has been breached. History Early mentions Collective security is one of the most promising approaches for peace and a valuable device for power management on an international scale. Cardinal Richelieu proposed a scheme for collective security in 1629, which was partially reflected in the 1648 Peace of Westphalia. In the eighteenth century many proposals were made for collective security arrangements, especially in Europe. The concept of a peaceful community of nations was outlined in 1795 in Immanuel Kant's Perpetual Peace: A Philosophical Sketch. Kant outlined the idea of a league of nations that would control conflict and promote peace between states. However, he argues for the establishment of a peaceful world community not in a sense that there be a global government but in the hope that each state would declare itself as a free state that respects its citizens and welcomes foreign visitors as fellow rational beings. His key argument is that a union of free states would promote peaceful society worldwide: therefore, in his view, there can be a perpetual peace shaped by the international community rather than by a world government. International cooperation to promote collective security originated in the Concert of Europe that developed after the Napoleonic Wars in the nineteenth century in an attempt to maintain the status quo between European states and so avoid war. This period also saw the development of international law with the first Geneva Conventions establishing laws about humanitarian relief during war and the international Hague Conventions of 1899 and 1907 governing rules of war and the peaceful settlement of