Norm contestation has become an established research programme in International Relations. However, scholars have yet to scrutinise the form and effect of radical contestation. I argue that radical contestation is a disruptive form of contestation, distinguished by (1) the extensive scope that attacks a specific norm and wider normative order, institutions, and actors sympathetic to the norm, and (2) high emotional intensity in animating contestation. To bring these features of radical contestation together, I use insights from the study of emotions and backlash movements to advance a new ‘emotional backlash’ framework and explain the construction, mobilisation, and outcome of radical contestation. I subsequently apply this framework to analyse the emotional backlash against Rohingya refugees during Covid-19. Cultivated by resentment, the emotional backlash against the Rohingya contests refugee protection norms and extends to radically challenge human rights advocates, United Nations agencies, and the larger humanitarian and cosmopolitan principles. In doing so, backlash supporters aim to restore a society without refugees and their sympathisers, and instead to promote racism as a ‘normal’ organising principle. By capturing radical contestation, this contribution steers norms scholarship towards a new research terrain and highlights the implications that the backlash has for the international refugee regime.