New Media and the Polarization of American Political Discourse


Matthew A. Baum and Tim Groeling. 2009. “New Media and the Polarization of American Political Discourse.” Political Communication . Publisher's Version


Scholars of political communication have long examined newsworthiness by focusing on the “gatekeepers,” or organizations involved in newsgathering (Lewin 1947, White 1950, Sigal 1973, Gans 1979). However, in recent years these gatekeeper organizations have increasingly been joined or even supplanted by “new media” competitors, including cable news, talk radio, and even amateur bloggers. The standards by which this new class of gatekeepers evaluates news are at best partially explained by prior studies focused on “professional” journalists. In this study, we seek to correct this oversight. We do so by content analyzing five online news sources – including wire service, cable news, and blog sites – in order to compare their gatekeeping decisions in the four months prior, and approximately three weeks immediately following, the 2006 midterm election. To determine each day’s major political news, we collected all stories from Reuters’ and AP’s “Top Political News” sections. We then investigated whether a given story was also chosen to appear on each wire’s Top News page (indicating greater perceived newsworthiness than those that were not chosen) and compare the wires’ editorial choices to those of more partisan blogs (from the left:, and from the right: and cable outlets ( We find evidence of greater partisan filtering on the latter three web sources, and relatively greater reliance on traditional newsworthiness criteria on the news wires.


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