Persuasion and dissuasion in political campaigns: Communication and media coverage in senate races

We estimate the persuasive and dissuasive effects of media-reported campaign-trail speech on candidate electoral performance using a model in which, during each bipartisan race, candidates choose whether to address partisan supporters or swing voters, newspapers choose whether to cover each remark, and reported speech moves turnout and voter support. The model captures a core tension: while candidates seek selective media amplification of their messages, media outlets chase the most polarizing content. Using text analysis to label more than 200,000 newspaper stories from 1980-2012 as partisan or swing voter-oriented, and linking those labels to high-frequency polls of U.S. Senate races, we estimate the model parameters that allow us to recover persuasive and dissuasive effects of campaign speech. We rely on instruments that exploit sports-driven crowding-out of political coverage. The estimates reveal that Democratic appeals to their base are approximately four times more effective at mobilizing partisan turnout than Republican appeals, but also provoke twice the level of backlash from swing voters. These offsetting forces moderate Democratic rhetoric and, because media outlets prefer partisan content, yield near-symmetric coverage of the two parties despite asymmetric mobilization returns.