Rivalry & Voting

    When we discussed public goods last week, we zeroed in on non-rivalry and non-excludability as defining characteristics of such a good. However, according to Buchanan’s Economic Theory of Clubs, many goods fall somewhere on a continuum of rivalry and publicness rather than a binary dichotomy of either rival or non-rival, private or public. This point is especially impactful for supposed non-rival goods, which, Buchanan argued, eventually reach a point of overcrowding. At this point, the good, though still technically available to you, gives you less than its possible utility because of the number of people you have to share it with. 

    As I read Johnson’s piece on voting, this conception of rivalry returned to mind. The ability to vote can be seen as a traditionally non-rival good; your exercise of your right to vote does not deny anyone else the ability to exercise their right to vote. The right to vote is not “consumed” when it is exercised. This principle of equal and unfettered access to the vote has been enshrined in American case law, such as Baker v. Carr, as well as in constitutional amendments. However, as Johnson points out, the utility you might get from voting certainly diminishes as more people exercise their right to vote. As more and more people use their right to vote, your vote goes from decisive to totally inconsequential. In fact, the probability that your vote will be the decisive one is so low that a rational person likely would not vote at all. These characteristics make the ability to vote seem more like a semi-rival good, one which is subject to a point of overcrowding, upon which it loses the utility it might otherwise endow. As the number of people who exercise their vote increases, p - the probability that your vote will be the decisive one - decreases, functionally reducing any marginal benefit you might derive from voting to 0. When some number of voters decide to exercise their right to vote, sufficiently reducing p, the right to vote essentially crosses a “threshold” of rivalry. After this threshold, the right to vote may as well have been “consumed,” for all the utility it offers an additional voter.