The Calculus of Consent: Logical Foundations of Constitutional Democracy is a book written by economists James M. Buchanan and Gordon Tullock in 1962.

The Calculus... is considered to be one of the classic works that founded the discipline of public choice in economics and political science.

Authors analyse the traditional political science approach to voting and how it views majority voting as the standard instead of the unanimity voting . They show that none of those systems are perfect, since there is always a tradeoff:

• a simple majority-based system imposes varying amounts of both external costs and decision-making costs
• a unanimity-based system has little or none external costs, but considerable decision-making costs

They conclude that decisions with potentially high external costs should be made in unanimity or at least in supermajority systems.

This work presents the basic principles of public choice theory. While many political scientists define the political process as a system in which the policy decisions are viewed as a private interest vs. public interest struggle, Buchanan and Tullock suggest that the public interest is simply the aggregation of private decision makers.

They show that in the classical political science theory, the "public interest" is always the correct choice with the same appeal to all voters, which may or may not be opposed by "special interests". But that theory ignores the fact that most choices appeal to many different "law consumers " with varying strengths.

An example to illustrate this point is a choice whether to increase funding for health care or not. Some voters will have very strong feelings for, some strong feelings against, but many voters may not care at all.

They compare this to a market transaction , where the voters strongly desiring the better health care could purchase the acceptance of the opposition and uninterested voters with concessions, resulting in an efficient allocation of resources (increasing the happiness of all parties - see Pareto optimum). However the equivalent of this in the political realm is that politicians buy the votes of other politicians (or groups of special interest) by promising to vote for their issues. In the opinion of authors of Consensus... such log-rolling is to be expected, but in the traditional political science theory, it is anomalous. Thus their model explains some things that the previous models of politics were not able to.

Table of Contents

Part I. The Conceptual Framework

• 1. Introduction
• 2. The Individualistic Postulate
• 3. Politics and the Economic Nexus
• 4. Individual Rationality in Social Choice

Part II. The Realm of Social Choice

• 5. The Organization of Human Activity
• 6. A Generalized Economic Theory of Constitutions
• 7. The Rule of Unanimity
• 8. The Costs of Decision-Making

Part III. Analyses of Decision-Making Rules

• 9. The Structure of the Models
• 10. Simple Majority Voting
• 11. Simple Majority Voting and the Theory of Games
• 12. Majority Rule , Game Theory, and Pareto Optimality
• 13. Pareto Optimality, External Costs, and Income Redistribution
• 14. The Range and Extent of Collective Action
• 15. Qualified Majority Voting Rules, Representation, and the Interdependence of Constitutional Variables
• 16. The Bicameral Legislature
• 17. The Orthodox Model of Majority Rule

Part IV. The Economics and the Ethics of Democracy

• 18. Democratic Ethics and Economic Efficiency
• 19. Pressure Groups , Special Interests , and the Constitution
• 20. The Politics of the Good Society
• Appendix 1 Marginal Notes on Reading Political Philosophy
• Appendix 2 Theoretical Forerunners

External link

• Ebook online at the Library of Economics and Liberty