Candidate quality, pressure group endorsements and the nature of political advertising

Candidates may vary in quality, where quality is some characteristic orthogonal to policy. This “simple modification” has for the most part defied integration into the Downsian framework. Here we add the following complicating factors. We consider the possibility that there are uninformed voters who are ignorant of the candidates' relative quality. However, a pressure group with inside information regarding the quality of the candidates may endorse one of the candidates as the high-quality candidate. We assume that the uninformed voters behave rationally in the presence of this endorsement. We demonstrate that truth telling by the pressure group is an equilibrium outcome. We also show that campaign endorsements by the pressure group are generally welfare improving even though the pressure group takes advantage of its private information.