‘No debate!’ is an imperative issued by some individuals with strong views about culturally salient moral or political issues. Inside academia, it shows up in refusals to cite or engage with work; refusals to share platforms; refusals to invite particular people to conferences or workshops. ‘No debate!’ is a common political tactic, often deployed by the side that enjoys the support of the public (why risk losing it?), and/or as a way of signalling the intensity of one’s moral judgement (just think how bad your view must be if I am willing to silence you over it!). In this talk I’m interested in the question of whether ‘no debate!’ is ever more than a political move. If it is sometimes unethical to debate: when, and why? And do the same normative considerations that apply in thinking about debate in the public sphere apply equally inside the university?