Lexical Ambiguity in Political Rhetoric: Why Morality Doesn't Fit in a Bag of Words

How do politicians use moral appeals in their rhetoric? Previous research suggests that morality plays an important role in elite communication and that the endorsement of specific values varies systematically across the ideological spectrum. We argue that this view is incomplete since it only focuses on whether certain values are endorsed and not how they are contextualized by politicians. Using a novel sentence embedding approach, we show that although liberal and conservative politicians use the same moral terms, they attach diverging meanings to these values. Accordingly, the politics of morality is not about the promotion of specific moral values per se but, rather, a competition over their respective meaning. Our results highlight that simple dictionary-based methods to measure moral rhetoric may be insufficient since they fail to account for the semantic contexts in which words are used and, therefore, risk overlooking important features of political communication and party competition.