The Responsibility to Protect (RtoP) has the potential to become a fundamental organising principle of modern international society. This principle emphasises that each state has the responsibility to prevent grave violations of human rights in its territory. It also - and this is its innovative dimension - assigns to the international community the task of supporting the implementation of this responsibility and of intervening if a state fails in its duty to protect. The aspiration and hope of those who support the emergence and development of RtoP is that the principle might assist in preventing repetitions of atrocities such as those that took place during past decades in Rwanda, Bosnia and Herzegovina (Srebrenica), and Sudan (Darfur).

The principle of RtoP has become the subject of many discussions in the United Nations, the European Union, other regional organisations, in national capitals, and civil society organisations. No longer merely a lofty ideal, it has become a political reality. Its normative power was demonstrated when, in the spring of 2011, the Security Council invoked RtoP in support of its decision to act on the situation in Libya. Many viewed the Libyan intervention, based on the responsibility of the international community, as a defining moment for the future development of the principle of RtoP.

Yet, it is precisely its invocation in the Libyan case that has raised fundamental questions concerning the powers, limitations and weaknesses of the principle of RtoP. Most critical, perhaps, is the question of whether RtoP allows for and could be (ab-)used to justify regime change in Libya.

Indeed, more than 10 years after its initial appearance, the jury is still out on the scope and potential role of RtoP. Can it indeed induce change in the oftenbemoaned tardiness of the international community's responses to mass atrocities? What instruments and procedures are best suited to address the causes of mass atrocities, so as to lead to actual prevention, rather than response? And on whom does the responsibility to protect actually rest: on the United Nations, regional organisations, individual states, or on all of these actors together? What can the doctrine deliver in terms of preventing a ‘pick-and-choose’ application of military force on the basis of selective geopolitical interests?

The present volume addresses these and other questions that are raised by the emergence of RtoP.