ECONOMY

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components—the benefit received if one’s favored candidate wins less the benefit
lost if the opposition wins and the marginal effect of voting on the election outcomes.
Marginal expected benefits approach zero if there is no difference between
the candidates or if one’s vote has an imperceptible effect on the election outcome.
If the median voter theorem holds, then the candidates do not differentiate and
there is no differential benefit to voting. Even if the candidates take distinct positions,
the marginal effect on the outcome is about nil if the electorate is sufficiently
large.
This logic implies that only those individuals whose votes make the difference between
winning and losing will vote. Ledyard (1984) proves that the Nash equilibrium
of a participation game is for voters to use a mixed strategy in which the probability
of voting is approximately zero for most voters, and slightly higher from those near
the median in a spatial model.
Downs further observes that this logic implies that an individual will not devote
much effort to learning about the electoral choices. It is not an optimizing strategy
to devote considerable time and effort to learning the details of the policy choices
presented by competing candidates and parties. It is rational to be politically ignorant.
Compounding this logic further is the incentive to free ride, as described in Mancur
Olson’s Logic of Collective Action. If ideologically similar people are going to vote or
learn about politics or participate in similar ways, why should I? Utility maximization
implies that individuals will give only small amounts of money to political campaigns
and will spend little time attending political meetings or engaging in other forms of
political action.
These two paradoxes are deeply troubling. They raise a fundamental question
about the power of the theory to explain vote choice, as well as turnout. Once the
individual is in the voting booth, what does the theory really predict about how
the individual will behave? If the action taken is to vote and to vote for a specific
candidate or party, the marginal expected utility of voting for a given candidate is still
exceedingly small. If voters have random utility functions, as is commonly conjectured
by empirical researchers working in this tradition, then the random component
surely dwarfs the marginal expected utility calculations of voting for one candidate or
another. It is hard, then, to entertain the notion that citizens are maximizing utility
when they vote.
One response to this logic is to reject the theory. Donald Green and Ian Shapiro
express this view most sharply in The Pathologies of Rational Choice. Reviewing the
empirical literature they argue that the basic empirical predictions regarding turnout
and competition suggest that the economic theory of democracy ought to be rejected
on empirical grounds. They are most troubled by the implications of the theory for
participation. Rational non-participation ought to be common, except in very close
or uncertain elections. However, closeness does not lead to much higher turnout, and
in very uncompetitive races people still vote at high rates—around 50 per cent in US
national elections and higher in other countries.
The paradoxes of rationality, however, apply broadly to democratic theory, not just
to economic reasoning. These problems are common sense, and have been considered