Political Support and Candidate Choice

This paper proposes a simple model of political supporters in an environment of spatial political competition. We assume that supporters are driven by sympathy for a candidate with similar preferences on their side of the policy space and by fear of a candidate with different preferences on the other side. If parties maximize support in their candidate selection, political platforms can diverge significantly. We show that radical candidates have a positive effect on support for the other party. If candidate choice internalizes this externality, platforms converge and overall support decreases to a minimum.