Gareth Evans, one of the key architects of 'responsibility to protect' (R2P), explores whether the World Summit endorsement of this concept in 2005 has helped the advance towards ending genocide and other major crimes against humanity. He examines whether the new norm has been implemented effectively in practice, or whether it remains simply inspirational and aspirational; whether this year's Security Council-endorsed military intervention in Libya constitutes a dramatic new benchmark for its application in extreme cases, or whether it represents the high-water mark from which the tide will now recede.