This study explores the source usage of three conservative and two progressive newspapers in Korea over the issue of beef imports from the United States. The purpose of the study is to understand the tendency of newspapers on both sides, which induced much turmoil, including huge demonstrations against the government in the middle of 2008. The results of a quantitative content analysis show that progressive newspapers employed more sources and presented the issue more negatively than conservative newspapers. In particular, progressive papers used more negative information, especially from experts, NGOs, and citizens, while the conservative papers used more positive information. In terms of information credibility and valence, the progressive papers effectively used NGO sources, which are situated in the middle of source credibility order, to present a negative tone. The order of credibility is as follows: experts (most credible), followed by judiciary, administration, parliament, NGOs, commercial businesses, and citizens (least credible).
