What explains the type of electoral campaign run by political parties? In this article, wo focus on the strategic unse of emotive language in campaign messages. We argue that the level of positive sentiment that parties adopt in their campaign messages depends on their incumbency status, their policy position, and objective economic conditions. We test these claims with a novel dataset containing information on the emotive language used in over 400 party manifestos across eight European countries from 1980 to 2012. As predicted, we find that incumbent parties, and incumbent prime ministerial parties in particular, use more positive sentiment than opposition parties. We find that ideologically moderate parties employ higher levels of positive sentiment than extremist ones. And we find that all parties exhibit lower levels of positive sentiment when the economy is performing poorly but that this negative effect is weaker for incumbents. Our analysis has important implications for research on campaign strategies and retrospective economic voting.
