Do political parties in the United States respond to public opinion when writing their official party platforms? Current research suggests a clear linkage between public opinion and party positions, with parties responding to public preferences, and public opinion responding to party messages. Drawing on existing research regarding the saliency/issue competition model of party position-taking, this study examines the specific effect of public opinion on party positions, positing that when a larger percentage of the public views a particular issue area as important, political parties will discuss that issue area to a greater degree in their official election platforms. To test this theoretical construct, we rely on public opinion data collected by Gallup, and normalized by the Policy Agendas Project, from 1947 through 2011, combined with content analyzed data regarding both the Republican and Democratic platforms from 1948 through 2012. Using OLS regression with a Prais-Winsten transformation and panel-corrected standard errors, we find support for the hypothesis that political parties discuss, in their platforms, issue areas that the public views as more important. Further, we find that this responsiveness does not appear to vary across political parties. These findings have important implications for our understandings of both political party dynamics and party representation in the United States. Moreover, these findings allow us to assess the health of American democracy.