Campaign advertising and voter welfare

This paper investigates the role of campaign advertising and the opportunity of legal restrictions on it. An electoral race is modeled as a signalling game with three classes of players: a continuum of voters, two candidates, and one interest group. The group has non-veri¯able insider information on the candidates' valence and, on the basis of this information, o®ers a contribution to each candidate in exchange for a favorable policy position. Candidates spend the contributions they receive on non-directly informative advertising. This paper shows that: (1) A separating equilibrium exists in which the group contributes to a candidate only if the insider information about that candidate is positive; (2) Although voters are fully rational, a ban on campaign advertising can be welfare-improving; and (3) Split contributions may arise in equilibrium (and should be prohibited).