Muddle Instead Of Music: The Electoral Consequences of Divergent Intra-party Positions on Immigration

Mainstream parties across Western Europe are in electoral decline. Yet existing explanations rarely consider how internal party heterogeneity shapes this trajectory. This paper argues that their decline is closely linked to their increasing difficulty in communicating clear and coherent messages on divisive cultural issues. Rather than treating party positions as fixed points, I conceptualize (and measure) them as distributions of stances expressed by internal actors. This reconceptualization makes visible how mainstream center-left and center-right parties (because of their broad electorates, organizational size, and ideological diversity) produce a wider positional dispersion in public communication. On issues such as immigration, this dispersion generates muddled communication that voters struggle to interpret, ultimately weakening electoral support. This argument extends existing work on party ambiguity by showing that much of the unclear communication produced by mainstream parties is not a deliberate electoral strategy but an involuntary outcome of their internal complexity. While strategic blurring can sometimes help parties navigate cross-cutting issues, mainstream parties increasingly lack the organizational cohesion and agency necessary to speak with one voice on issues that necessitate a clear position. The resulting positional dispersion reflects structural constraints rather than strategic choice, challenging common interpretations that equate ambiguity with intentional vote-seeking. Empirically, the paper employs a two-step design. First, I analyze expert disagreement in the Chapel Hill Expert Survey (CHES) to show that mainstream center-left and center-right parties exhibit systematically greater positional ambiguity on cultural issues but not on economic ones. Second, I develop a novel computational measure of positional distributions using over one million Tweets from German MPs (2013-2021), applying open-source large language models to detect issue-specific stances at scale. Aggregating individual MP positions to monthly party-level distributions, I link positional dispersion to longitudinal polling data and an independent measure of immigration salience derived from German public news coverage. The results demonstrate that mainstream parties are more prone to exhibit a higher ambiguity on cultural issues and that this higher positional dispersion significantly depresses mainstream party support. Notably, increased issue salience does not amplify this effect. By theorizing and measuring party positions as distributions, the paper advances the study of political ambiguity beyond strategic accounts. It highlights how organizational complexity shapes democratic representation and helps explain why mainstream parties are increasingly ill-equipped to compete on salient cultural issues in contemporary Western Europe, which directly feeds into their electoral decline.