Policy Platforms, Campaign Spending and Voter Participation

We model electoral competition between two parties in a winner-take-all election. Parties choose strategically first their platforms and then their campaign spending under aggregate uncertainty about voters' preferences. We use the model to examine why campaign spending in the United States has increased at the same time that politics has become more polarized. We find that the popular explanation ­ better targeting of campaign spending ­ is not a likely explanation. While better targeting does lead to greater spending, it leads to less polarization. Instead we argue that the likely explanation is that voters references have become more volatile. This will both raise campaign spending and increase polarization. At the same time it is consistent with the observation that voters have become less committed to the two parties.