As a policy which presumes to be based on a norm of “good neighbourliness” the European Neighbourhood Policy (ENP) depends for legitimacy on interpretation and understanding of an extremely complex human association. This essay focuses on the rhetorical dynamics involved in the neighbourhood policy and their consequences in terms of external input legitimacy. An analysis of the main policy documents between 2003 and 2015 suggests that the ENP cannot be dismissed either as a rhetorical ruse to promote EU power interests, or a naïve vision of good-natured cohabitation. Even if the neighbourhood discourse was introduced to cover a policy of tranquilization or subjugation, it still communicates and supports key norms and ethical standards of international relations. Arguably, this amounts to a dilemma in terms of external input legitimacy: The commitment to a responsive and reflective order among neighbours is quite visible, but so are the elements of conditionality and differentiation.