From the publisher: There is growing interest among scholars and advocates in the way that the nascent norm of the Responsibility to Protect (R2P) is diffusing at the regional level. This article critically explores the spread of R2P in Southeast Asia against the backdrop of recent scholarship on norm localization. It argues that, contrary to some recent analyses, the R2P norm has not been localized in Southeast Asia. Constitutive localization requires the active borrowing of transnational norms by local or regional actors who build congruence with local practices. Although some regional states have used the language of ‘sovereignty as responsibility’ there are few signs that local actors are driving the reception of the norm in the region, nor have they institutionalized it. Rather, outsider proponents are the primary advocates and the norm lacks a champion or well-connected ‘insider’ proponent among regional governments or civil society groups. Second, despite an energetic campaign by advocates, emphasizing consensual and capacity-building activities, many governments are still wary of R2P as a potential threat to sovereignty and regime security. As a result, regional states have taken an ‘à la carte’ approach to R2P, accepting aspects of the R2P agenda that they find least threatening or that support their national interests, while ignoring or quietly resisting those they find challenging. Rather than localization, what we are seeing with respect to R2P in Southeast Asia is a dramatic change in the way outsiders are reframing the norm.