Legislators and Interest Groups: How Unorganized Interests Get Represented

This paper derives a supply price for public policy using a constrained maximization model. In the model, three sets of agents each have preferences over outcomes: organized interest groups offer campaign contributions to improve their own wealth, voters offer votes to obtain outcomes closer to their most preferred outcomes, and legislators seek both campaign contributions and votes to obtain reelection. A given legislator's supply price for policy is shown to depend on the productivity of his effort, as determined by committee assignments, priority and ability, and by the preferences of his unorganized constituency in the home district. Two extreme assumptions about the effectiveness of campaign spending in eliciting votes are used to illustrate the comparative statics properties of the model. The prediction of the model is that interest groups will, in general, seek out legislators whose voters are indifferent to the policy the interest group seeks. Thus, voters who do have preferences over policy are in effect represented, even though they are not organized.