Jumping Ship or Jumping on the Bandwagon: When Do Local Politicians Support National Candidates?

Local politicians are often expected to mobilize voters on behalf of copartisan candidates for national office. Yet this requirement is difficult to enforce because the effort of local politicians cannot be easily monitored and the promise of rewards in exchange for help is not fully credible. Using a formal model, we show that the incentives of local politicians to mobilize voters on behalf of their party depend on the proportion of copartisan officials in a district. Having many copartisan officials means that the party is more likely to capture the district, but the effort of each local politician is less likely either to be noticed by higher-level officials or to make a difference on the election outcome, thus discouraging lower-level officials from exerting effort. We validate these claims with data from federal elections in Mexico between 2000 and 2012. In line with the argument, the results show that political parties fail to draw great mobilization advantages from simultaneously controlling multiple offices.