LS403Z: LAW AND DEMOCRACY: VOTING METHODS, AND SOCIAL CHOICE THEORY (2026-2027)

Social Choice Theory explores how groups of people make decisions together. The most important question is do any of these methods actually accurately deliver the consensus of the group into a singular voice? Or do some of these methods have serious hidden defects, making one member more powerful than other members, do they tilt the voting outcome unfairly, or does dictatorship or chaos lurk in the voting mechanisms? These and other key questions are the focus of research in Social Choice Theory. 

This course provides a rich introduction to Social Choice Theory and its nexus and applications within legal rules and legal institutions. The understanding of how courts and committees really work, how voting really works, is as equally powerful as it is often counter-intuitive. Knowledge gained in this course is highly effective in many legal settings, supporting a student in their legal career. 

When we speak of law and justice, it is almost always a sense of group efforts and decisions. Legislatures vote to approve new laws, parliamentary committees vote on a number of issues and resolutions before bills can be presented to the legislature, juries vote to determine if a party is innocent or liable, a panel of judges votes to determine legal outcomes, and citizens vote in elections to enable all of the above legal institutions to work and function. Voting and group decision making is a core activity within all legal institutions, but especially for democracy and various communal modes of governance. 

While research continues to evolve and emerge, a foreseeable exemplar sequence of seminars could cover this range of material: 

Voting in Frustration: A seminar that introduces the history of legal theorists and political revolutionaries to develop superior modes of voting and group decision making. From the Roman senator Pliny the Younger, who made early comments on how voting choices can be set up strategically to bias outcomes, to Jean-Charles de Borda ('Borda'), and Marie Jean Antoine Nicolas de Caritat, Marquis de Condorcet ('Condorcet') trying to improve majority voting to avoid such biases, to more recent efforts by mathematicians Edward Nanson and by the Oxford mathematician Charles Dodgson, better known as Lewis Carroll, plus other voting models used today. Those models lead to the surprise discovery by Ken Arrow that bias-free voting processes are impossible, if we expect certain rational behaviors in voting. The seminar will show how Arrow's discovery kicked off the field of Social Choice Theory, leading to Gibbard-Satterthwaite theorem's ferocious results, and what it implies for all democracies, trials, and legislative voting processes. 

Committees and Power: A seminar that explores the 'mysteries' of committee decision-making and voting power within the committee members. This seminar will cover the research into why is it that when voting powers are distributed equally across committee members, some members will be able to win substantially more often than other committee members on various voting questions. This area of Social Choice Theory is known as the 'power index' theories. This seminar covers the research of Lionel Penrose, John Banzhaf, Lloyd Shapley, and Martin Shubik. 

How Elections are Won: A seminar that discusses voting rules and elections from a more macro view, looking at the research agendas initiated the Scottish scholar Duncan Black with his "median voter" model and Harold Hotelling's and Anthony Down's spatial economy model- the two key models used to forecast who would win an election. Both of these models describe how voters cluster in major elections and how that impacts the final results. We'll also learn about Maurice Duverger's Law, that "simple-majority single- ballot systems" have mathematical properties which lend to a two party system emerging over multiple elections. Duverger's Law was extended and proven by the research of Gary Cox, William H. Riker, and Arend Lijphart, who have all demonstrated and extended this Law both theoretically and empirically. This seminar provides much understanding into how elections work and how actors can position themselves to win more often. 

Juries and the Wisdom of Legislatures: A seminar that explores the implications of Condorcet's Jury Theorem, a highly controversial intellectual idea that was intended to bedrock the foundations of the French Parliament in scientific rigor. Condorcet argued that when a pool of voter exists whose likelihood of correct decision making is better than 50/50, then the more voters you engage the more likely the outcome is to be correct. Ultimately, this is a very important concept, in that it raises under what conditions a large group of voters can be expected to make the right decisions. Beyond Condorcet, Lijphart, Black, Bernard Gorman, Scott Feld, and Guillermo Owen developed models where shared knowledge or shared preferences could weaken Condorcet's claims of success. David Austen-Smith and Jeffrey Banks provided models of strategic voting which also undermined Condorcet's hopes. List and Robert Goodin expanded the whole model, opening new lines of thought. Seem wisdom from legislatures remains a solid research! 

Anticommons: While many are concerned for the governance of the Commons to prevent tragedy of over- exploitation, it turns out that the inverse phenomena might actually be worse, the Anticommons. While commons are what results when no one has exclusive rights over a property or a decision process, anticommons are what results when EVERYONE has exclusive rights over a property or a decision process. This can prevent any activity from even beginning;

Information on contact teaching time is available from the course guide.

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There are no assessments for this course.