The United Nations is the only universal body. Its unique role in peacekeeping cannot be arrogated by other organisations, which would lack legitimacy. The argument of military efficiency, or financial resources, cannot be a substitute. Isolationism of the inter-war period undermined the authority of the League of Nations. The UN, to be successful, needs the engagement of all the Member States.
Consensual peacekeeping is most successful.
Doctrines of intervention without consent of the States parties need to be treated with caution. We are witnessing two divergent trends in international relations. While there are fewer resources available for development cooperation, there is greater tendency to intervene in the domestic jurisdiction of States. There is a dichotomy between disengagement from international commitment on one area and greater intervention in other areas. Both the assumption, and the prescription, are questionable.