Management Summary Research Study „Truth-Commitment and Constitutional Choice”
This study examines how citizens’ belief in the existence of moral truths in politics shapes the choice of constitutional decision rules. It builds on the classic framework of The Calculus of Consent by James M. Buchanan and Gordon Tullock, in which the optimal rule minimizes the sum of two costs: external costs (the expected losses borne by those who are outvoted) and decision costs (the resources required to reach agreement). The author introduces a new parameter – the intensity of belief in moral truth in the polity – and formally demonstrates how this parameter shifts both cost schedules. Two main results follow. First, the optimal adoption threshold tightens when stronger truth-commitment raises marginal external costs more than marginal decision costs, and loosens in the reverse case; under a plausible configuration, higher conviction implies stricter rules. Second, even at the optimally chosen rule, the total minimized cost rises whenever truth-commitment increases either of its components. Extensions show how consensus and conviction operate as orthogonal channels, how constitutional rights can substitute for higher thresholds, how heterogeneity in conviction aggregates across individuals, and how moralized perceptions distort observed rules. The study thus provides a contractarian rationale for Buchanan’s skepticism toward truth-based politics and yields testable implications for institutional design.
Target groups of stakeholders: Constitutional policymakers, legal and political philosophers, economists and political scientists working on public choice and institutional economics, journalists covering constitutional reform and democratic legitimacy.
Citation: Berggren, N. (2026). Truth-commitment and constitutional choice. Rationality and Society. Advance online publication.