Coattails and the forces that drive them: Evidence from Mexico

Coattails and the forces behind them have important implications for the understanding of electoral processes and their outcomes. By focusing our attention on neighboring electoral sections that face the same local congressional election, but different municipal elections, and assuming that political preferences for local legislative candidates remain constant across neighboring electoral sections, we exploit variation in the strength of the municipal candidates in each of these electoral sections to estimate coattails from municipal to local congressional elections in Mexico. A one percentage increase in vote share for a municipal candidate translates, depending on his or her party, into an average of between 0.45 and 0.78 percentage point increase in vote share for the legislative candidates from the same party (though this effect may not have been sufficient to affect an outcome in any electoral district in our sample). In addition, we find that a large fraction of the effect is driven by individuals switching their vote decision in the legislative election, rather than by an increase in turnout.