The release of former CBS reporter Bernard Goldberg's book, "Bias," first prompted our examination of the degree to which the news media deviate from objective coverage. Mr. Goldberg wrote of how, during Bill Clinton's impeachment trial, Peter Jennings consistently labeled Republican loyalists as "conservatives" or "very determined conservatives." Meanwhile, the ABC News anchor did not refer to Democratic loyalists as "liberals," treating Mr. Clinton's allies, instead, as mainstream lawmakers. So we asked ourselves, was the media's tendency to label particular senators isolated to the Clinton impeachment trial? Or is there a more pernicious generality? After a study of New York...