Ambiguity and extremism in elections

"We analyze a model in which voters are uncertain about the policy preferences of candidates. Two forces affect the probability of electoral success: proximity to the median voter and campaign contributions. First, we show how campaign contributions affect elections. Then we show how the candidates may wish to announce a range of policy preferences, rather than a single point. This strategic ambiguity balances voter beliefs about the appeal of candidates both to the median voter and to the campaign contributors. If primaries precede a general election, they add another incentive for ambiguity, because in the primaries the candidates do not want to reveal too much information, to maintain some freedom of movement in the policy space for the general election. Ambiguity has an option value"--National Bureau of Economic Research web site.