The responsibility to protect (R2P) is a new norm or set of principles that redefines sovereignty as a responsibility rather than as a privilege or a means of control, which offers a policy guideline on when and how the international community should intervene for the sake of human protection in the face of mass atrocity crimes. Just as in humanitarian intervention, however, the R2P faces several dilemmas: How serious should humanitarian emergencies be to warrant international intervention? Why did we need intervention in Libya while not in Syria where the situation seems to have been more serious than Libya in terms of the necessity of civilian protection? How can the narrowly defined R2P crimes accommodate those suffering in complex humanitarian crises? Is it feasible for the international community to opt for military intervention in North Korea based on the principles of the R2P if a crisis occurs as it did in Libya? Along the line of these inquiries, the paper reviews the concept and debates of the R2P, discusses the possibility of the R2P applied to the real world through examining cases such as Libya, Syria, Sudan Darfur, and Myanmar. Also, the feasibility and validity of expanding the R2P scope, only limited to the "four R2P crimes(i.e. genocide, ethnic cleansing, war crimes, and crimes against humanity), will be assessed, with particular emphasis on the practical implications for the case of North Korea