Cross-cutting Messages and Voter Turnout: Evidence from a Same-Sex Marriage Amendment

Does disagreement stimulate political participation, or discourage it? Some researchers find that exposure to cross-cutting views demobilizes voters. Selection bias in the way individuals expose themselves to disagreement and other sources of endogeneity pose challenges to causal inference. I address these concerns by using an experimental design that exogenously assigns cross-cutting or reinforcing messages. A random sample of North Carolina Democrats and Republicans received postcards summarizing either liberal or conservative opinions on a statewide same-sex marriage amendment. I find that individuals exposed to disagreement demobilize by 1.0 to 1.6 percentage points, with the majority of the combined effect attributable to a 2.0-percentage point decrease in turnout among Republicans receiving a Democratic message. I observe a similar level of demobilization when defining disagreement on the basis of predicted issue position on same-sex marriage in place of partisan affiliation. The effects are strongest among moderate supporters of traditional marriage that receive a cross-cutting treatment. The experimental design thus enables causal evidence on the nuanced interactions between political or issue position and exposure to campaign information from the opposing side.