Campaign spending with office-seeking politicians, rational voters, and multiple lobbies

I introduce a microfounded model of campaign ¯nance with o±ce-seeking politicians, a continuum of voters, and a large number of heterogeneous lobbies. Lobbies make contributions to politicians according to a common agency framework. Politicians use contributions to ¯nance their electoral expenditures. Voters are not fooled by electoral expenditures: they are in°uenced in a way that is consistent with the equilibrium behavior of lobbies and politicians. The model is used to: (i) determine the relation between campaign spending and political deadweight; (ii) show the informational value of lobbies' contributions; (iii) evaluate the welfare implications of restricting campaign spending; and (iv) interpret the empirical ¯nding that campaign expenditures have a very low e®ect on election outcome. One can say that this model makes the best case in favor of campaign contributions. Nevertheless, under reasonable parameter values, a ban on campaign contributions is welfare-improving.