Since the early 1990s, UN responses to protracted crises have evolved from a focus on ‘transitions’, to parallel humanitarian and development activity, to ‘strategic frameworks’ and ‘integration’. The response agenda was driven by the interaction of concepts such as human development and human security, as well as the interest-based politics of member states and the bureaucratic politics of the UN. Only occasionally have policy concepts been translated into operational tools. Today, there is growing interest in expanding the UN’s role in protracted crises and post-conflict operations. This paper looks at the challenges facing the UN which need to be resolved, including maintaining political independence from powerful member states, ensuring staff security and advancing shared policies for implementation.