Legislative function as an argumentative practice:

Foundations for a model of the rational-argumentative legislator

Abstract

This article analyzes the legislative function through the lens  of legal argumentation theory, questioning its traditional exclusion from standards of rationality predominantly developed in relation to judicial decision-making. Drawing on post-positivist constitutionalism and the theoretical contributions of Atienza, Alexy and Perelman, as well as the debate on legislative rationality, it argues that the legislator likewise engages in an argumentative practice, although neither directly nor identically to judges, and is subject to duties of public justification, constitutional coherence and inclusive deliberation. By delineating the functional similarities and structural differences between judicial and legislative argumentation, the article contends that legislative decision-making is subject to requirements of argumentative rationality articulated in functionally equivalent, though not identical, terms to judicial standards. On this basis, it proposes a model of the rational-argumentative legislator, conceived as a guarantor of the rationality of law and as a mechanism for transforming political power into reasons that can be publicly justified, as a condition of democratic legitimacy.