A Characterization of Black’s Voting Rule

• Authors: Salvador Barberà and Walter Bossert
• Public Choice.July 2026

In his 1958 classic, The Theory of Committees and Elections, Duncan Black proposes the following lexicographic choice rule: for any set of feasible candidates, and any profile of voters’ preference relations, choose the strong Condorcet winner if it exists, and select the set of Borda winners otherwise. We provide a novel axiomatic characterization of this proposal. We do so by means of the social welfare functions that underlie the rule’s choices, and the use of axioms that emphasize what is common and what is different in the spirit of the amply debated proposals made by these two eighteenth-century authors.