Foreign Policy in a Time of Polarization: Evidence from the Joint Comprehensive Plan of Action

On July 14, 2015, when Iran, the United States, and five other countries reached the Joint Comprehensive Plan of Act (JCPOA), commonly referred to as the Iran nuclear deal, 59% of informed Democrats approved of the deal, compared to only 14% of informed Republicans. This controversy is remarkable, especially because foreign policy rarely grips the American public's attention as much as issues of domestic policy. Usually, Americans are more concerned about their taxes or health care than they are about the United States's dealings with another country. When the JCPOA was reached, though, 79% of Americans reported hearing at least a little about it. Of those who had heard about the deal, 86% ventured an opinion in favor or against it. This data raises two questions: first, why did the JCPOA capture public attention in the way that it did? And second, how did the public become so polarized around this issue, specifically? This study argues that traditional models of understanding the way the media influences public opinion are useful, but that in some cases, the effects of media coverage on public opinion outcomes are only comprehensible if we imagine two distinct publics: a Republican one, and a Democratic one. By tracking news coverage and public opinion polling data over time, this study maps out the story of the JCPOA. The news coverage and polling data demonstrate how the way an issue is framed by the media relates to the way the public perceives that issue. This study hypothesizes that an interaction between elite interests and media coverage influenced the public's perception of the JCPOA, both in holding the public's interest and in sparking support for and opposition against the deal along partisan lines. Ultimately, the deal's opposition successfully activated the Republican public but was unable to stop the JCPOA from going through in 2015. However, the JCPOA was easily reversible, due to its features as an executive agreement and possibly due to the opposition's success in activating the Republican base.