Since the Treaty of Westphalia, sovereignty has been backed by the norm of nonintervention. By contrast, the responsibility to protect (R2P) strikes a balance between unauthorised unilateral interventions and institutionalised indifference. With a rapidly deteriorating humanitarian situation in Libya in early 2011, the United Nations (UN) authorised the use of force to protect an imminent slaughter of civilians but prohibited taking sides in the internal civil war, intervening with ground troops, or effecting forcible regime change. The record of NATO actions in Libya marks a triumph for R2P but also raises questions about how to prevent the abuse of UN authority to use international force for purposes beyond human protection.