Agonist theorists have argued against deliberative democrats that democratic institutions should not seek to establish a rational consensus, but rather allow political disagreements to be expressed in an adversarial form. But democratic agonism is not antagonism: some restriction of the plurality of admissible expressions is not incompatible with a legitimate public sphere. However, is it generally possible to grant this distinction between antagonism and agonism without accepting normative standards in public discourse that saliently resemble those advocated by (some) deliberative democrats? In this paper we provide an analysis of one important aspect of political communication, the use of slippery slope arguments, and show that the fact of pluralism weakens the agonists’ case for contestation as a sufficient ingredient for appropriately democratic public discourse. We illustrate that contention by identifying two specific kinds of what we call pluralism slippery slopes, i.e. mechanisms whereby pluralism reinforces the efficacy of slippery slope arguments.