Matt Guardino and Danny Hayes have examined every story about Iraq that appeared on ABC and CBS between August 1, 2002, and the beginning of the war, March 19, 2003 — 908 stories in all.
Their main conclusion is:
bq. Bush administration officials were the most frequently quoted sources, the voices of anti-war groups and opposition Democrats were barely audible, and the overall thrust of coverage favored a pro-war perspective.
Dissenting views did appear, but, notably, they came not from domestic sources, such as Democrats and others opposed to the war:
bq. Instead of emanating from Democratic elites, leaders of the anti-war movement within the United States, or other sources of domestic dissent, however, the campaign against a war—at least according to network TV news—was spearheaded by Saddam Hussein and other foreign leaders.
Guardino and Hayes note that perhaps relying on Hussein and, say, Jacques Chirac doesn’t put the anti-war case in the best possible light:
bq. But by going overseas for that perspective—to France, Germany, Iraq, and elsewhere—the anti-war view was accorded a difficult position, from the perspective of domestic public opinion. It is well known that source credibility is central to the persuasiveness of communication, political or otherwise. And while many Americans were skeptical of the Bush administration’s motivations for a confrontation with Iraq, we would surmise that even greater skepticism infused Americans’ perceptions of Saddam Hussein’s arguments about why war was a bad idea.
That is putting it mildly, needless to say. The paper is here.