A study was conducted to explore the influence of newspaper editorial campaign endorsements. The study examined the Louisville (Kentucky) "Courier-Journal," which tends to endorse Democratic candidates, and the Chicago "Tribune," which tends to endorse Republican candidates. It was hypothesized that readers would show higher awareness of editorial endorsements in these two prestige papers than of those in competing papers in the same communities; that readers would see these prestige papers as more balanced and less biased than competing papers in campaign news coverage; and that readers inclined to vote against the endorsed candidate would view the paper as more biased in favor of that candidate than would voters who favored the endorsed candidate. Telephone surveys of 456 residents of Louisville and 364 Chicago residents were conducted. Content analysis of the two papers was conducted from the start of the 1984 presidential campaign through election day. Television network news coverage was also analyzed. Although the great majority of respondents was unaware of which candidate had been endorsed by the paper they read, the readers of the two prestige papers were more likely to know than were readers of the other papers, as hypothesized. The second hypothesis was not supported, while the third received tentative support. (HTH)