This article proposes a way of connecting two levels at which scholars have studied discursive practices from a normative perspective: on the one hand, local transactions-face-to-face arguments or dialogues-and broadly dispersed public debates on the other. To help focus my analysis, I select two representatives of work at these two levels: the pragmadialectical model of critical discussion and Habermas's discourse theory of politicallegal deliberation. The two models confront complementary challenges that arise from gaps between their prescriptions and contexts of actual (...) discourse. In response, I propose a theory of argument cogency that distinguishes three kinds of merit: content, transactional, and public. Normative links between the two levels arise through the ways argument contents spread across multiple transactions in a social space whose structure and composition favor collective reasonableness. (shrink)