Most American political campaigns use social media as one component of a broader communication strategy. Campaign use of social media is typically governed by controlled interactivity, a philosophy that attempts to leverage citizens’ online behavior toward the goal of electing the candidate. One key outcome of controlled interactivity is high levels of message discipline, the degree of correspondence between a campaign’s and its audience’s political speech. This study quantifies message discipline as it flows through two highly visible controlled-interactive spaces—Barack Obama’s and Mitt Romney’s respective official campaign Facebook pages—during the 2012 U.S. presidential campaign. The results of a lexicon analysis indicate that Romney’s campaign controlled its audience’s interactivity more effectively than the Obama campaign and that both audiences departed from message discipline most sharply on the issues of civil rights and religion.