Campaign Comparative Advantage and Partisan Polarization

• In Event: Party Polarization in Canada and the United States

Abstract

The goal of this paper is to explain what Nolan McCarty (2019) describes as polarization through divergence. This divergence is one of the core features of contemporary partisan polarization in the US and describes the phenomenon by which Republicans and Democrats represent districts that are identical in their underlying partisanship in very different ways (McCarty, 2019, 103). Members of the House, in other words, have voting records that increasingly diverge from district preferences.

I seek insights on partisan divergence based on a theory of campaign comparative advantage. I argue that divergence has risen because Republican and Democratic candidates have specialized in distinct campaign technologies to mobilize voters. Republican candidates are more likely to rely on television advertising while Democratic candidates turn more frequently to GOTV programs that require volunteer labor. Those technologies, however, are more effective in particular district environments. Mobilizing voters through TV spots, and thus Republican candidates, will have the advantage where advertising is cheap, while GOTV campaigns and Democratic candidates will have the edge in districts with greater access to volunteer labor. Thus, and based on district characteristics separate from ideology, the candidate for one or other party can often achieve a campaign comparative advantage; they can mobilize voters more effectively than the other side. This unobserved, but latent, advantage enables legislators to pursue more extreme policies in office, and still be viable candidates, and therefore fosters polarization (similar to the exploitation of “slack” in economic optimization). If this hypothesis is correct, then Republicans (Democrats) should be more (less) extreme, controlling for district ideology, in districts in which television advertising is cheap and less (more) extreme in congressional districts that are well-endowed with sources of volunteer labor, especially public sector unions.

The empirical component of the data proceeds in two steps. In the first section, data from the Wesleyan Media Project from 2012 to 2016 is used to document the broader use of television advertising by Republican challengers, especially primary challengers, compared to Democratic counterparts and to confirm whether campaign advertising is responsive to the cost of advertising by district. The second section tests the hypothesis outlined above, for the years 1973 to 2012, a forty year period for which we have industry data on media markets and their cost and before the greater adoption of social media as a disruptive technology. The hypothesis is tested using DW-NOMINATE scores to measure the ideology of US Representatives, data from industry sources to generate a proxy measure of advertising costs by district and census data on public sector union density by district. The final section of the paper summarizes the degree to which we can explain partisan divergence through central features of campaigns and elections. I conclude with an assessment of why parties have increasingly specialized in divergent campaign technologies and how this relates to the literature on the “hollowing out” of parties.

Author

• Lucy M. Goodhart, Brandeis University