Educating the Least Informed: Group Endorsements in a Grassroots Campaign*

Scholars of political campaigns have focused on traditional mobilization efforts where a political party or interest group targets core supporters and undecided independents. Yet campaigns are increasingly targeting persuadable members of the opposition. If people are merely responding to the message, then nontraditional strategies could be effective despite the fact that it is delivered by an opposition political group. However, there are strong theoretical reasons to expect that people consider the source of a message in addition to the content of the message (e.g., Druckman 2001; Lau and Redlawsk 2001; Lupia 1994). We study the competing effects of message and source cues with a field experiment conducted during the 2006 election in two highly competitive Pennsylvania statehouse races where a well-known liberal activist group endorsed Democratic candidates and canvassed both core supporters and Republicans they thought to be persuadable. The group allowed us to randomly assign individuals to receive a door-to-door contact or phone call from its campaign workers. After the election, we measured the political preferences of subjects in the treatment and control groups with a telephone survey. Our results reveal that Republicans used the endorsement as a negative voting cue, and that the group’s endorsement helped some Republicans compensate for their lack of political awareness. We conclude by discussing the theoretical and practical implications of these findings.