It is not only what you say, it is also how you say it: The strategic use of campaign sentiment

What explains the type of electoral campaign run by political parties? We provide a new perspective on campaigns that focuses on the strategic use of emotive language. We argue that the level of positive sentiment parties adopt in their campaigns depends on their incumbency status, their policy position, and objective economic conditions. We test these claims with a novel data set that captures the emotive language used in over 400 party manifestos across eight European countries. As predicted, we find that incumbent parties, particularly incumbent prime ministerial parties, use more positive sentiment than opposition parties. We find that ideologically moderate parties employ higher levels of positive sentiment than extremist parties. 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 voting.