After the Holocaust, the world vowed it would 'never again!' permit such mass atrocity crimes, yet many have since gone unchecked, from the killing fields of Cambodia to the machetes of Rwanda to the ongoing nightmare in Darfur. Gareth Evans, president of the International Crisis Group, explains this lack of government action. In a more hopeful vein, however, he also shows how the emergence of a new international norm can protect the peoples of the world from mass crimes.The Responsibility to Protect (or R2P) concept was born in 2001 and embraced at the UN World Summit in 2005. The heart of this new international norm is the belief that if sovereign governments fail to protect their own people from genocide, ethnic cleansing, or other major crimes against humanity, then the wider international community must take whatever action is appropriate. The new norm emphasizes assistance and prevention, not coercion, but it also accepts that it is sometimes right to fight. The bottom line is that the world cannot just stand by. 'Never again' is still more a hope than a promise, however. The 2005 consensus remains politically fragile, with many developing states worrying that R2P goes too far or is too easily capable of misuse by major powers. Political will must be solidified, and effective institutional capacity must be created.This important book meets these challenges head on, clarifying misunderstandings about the new norm's scope and limits and spelling out the steps needed to make R2P work in practice. Evans shows how Responsibility to Protect is far better equipped to end mass atrocity crimes than is 'the right to intervene' or any other 'humanitarian intervention' doctrine of the past. The book is enlivened throughout by real-world examples, analyses of current events, and assessments drawn from the author's own vast experience.