NPR:
"The Bush campaign has a tendency to attack more on character than the Kerry campaign. And historically from 1952 to 2000, we have found that Republicans--and there are exceptions--tend to attack more on character; Democrats as a group tend to attack more on policy than Republicans. So that general tendency seems to be followed into the 2004 campaign.
Although some studies have shown that voters, particularly late-deciding moderates, can be turned off by negative attacks, this year it appears the candidates have decided there is little risk to attacking and much to gain."