Measuring Escalating Hostility and Democratic Backsliding. Proof of Concept for the “Political Hostility Scale (PHOS-16)”

Hostile political rhetoric has become increasingly prominent in modern democracies, as elite polarization has moved well beyond policy disagreement and conventional contestation to encompass inflammatory language, nasty attacks, and even party leaders vocalizing prejudicing measures against political rivals. This shift towards polarizing rhetoric coincides with episodes of political violence across the world, raising concerns about how elites’ discourse fuel their supporters’ radical negative view against their political opponents (Nai et al. 2025), which can lead to violent behaviour among supporters. Our contribution seeks to evaluate these transformations in elite rhetoric by providing a comprehensive framework to monitor the escalating hostility across countries and over time. While previous scholarship has attempted to move beyond encompassing concepts such as “polarizing” rhetoric – distinguishing specific dimensions such as different levels of incivility and intolerance (Papacharissi 2004; Muddiman 2017; Rossini 2020; Vargiu et al. 2024) – those attempts are not sufficiently integrated to describe the broader spectrum of today’s level of belligerence. Moreover, current frameworks shall consider the most violent expression of elite rhetoric. For that goal, our PHOS project presents a proof-of-concept based on the theoretical foundations of the Hostility Scale (Dodeigne 2025), testing 16 fine-grained indicators to evaluate escalating hostility in elites’ political rhetoric. PHOS-16 ranges from adversarial hostility (4 items), incivility (3 items), intolerance (4 items) and belligerence (5 items). It furthermore introduces a normative threshold distinguishing between agonist rhetoric, and antagonist discourses that undermine the functioning of democracies. For this proof of concept, we rely on four types of empirical data testing the danger of polarizing rhetoric for democracy using (1) a global expert survey (n=507 worldwide), (2) a conjoint experiment with voters (N=4.700 in Flanders and Wallonia – Belgium), (3) a content analysis of Twitter/X posts by Donald J. Trump (N= 32.582 posts between 2015 and 2021), and (4) an elite survey (N=170 Belgian MPs). Overall, preliminary empirical analyses converge and establish the reliability and consistency of PHOS-16 as a measurement tool for detecting shifts in hostile rhetoric and its danger for democracies. First, the expert survey conducted worldwide confirms the escalating degree of the 16 levels of hostile communication as well as the flipping point towards antagonist rhetoric incompatible with democracy. Second, the content analysis of Donald J. Trump’s post on Twitter/X tends to suggest a “ratchet effect”, by which upper levels of antagonism are reached a sequenced manner (from incivility to intolerance, and from intolerance to belligerence). It culminated in Donald J. Trump’s calls for violent actions during the 2021 Storming of the Capitol, and the proclamation of the “rigged” 2020 presidential elections. Analyses are still pending for the conjoint experiment with voters and the elite survey. Overall, by providing fine-grained indicators of conceptual and normative dimensions of hostility, PHOS-16 offers the first systematic reliable tool to assess transformations of hostile rhetoric and its consequences for the functioning of democracies.