Media Communication About a Climate Assembly as a Deliberative Bridge? Heterogeneity in Public Attitude Responses to Contrasting Media Framings of a Deliberative Minipublic.

The potential role of deliberative mini-publics (DMPs) as a trusted intermediary to inform public deliberation on complex policy areas has long been discussed, but with limited empirical evidence. Ongoing politicisation of, and political polarisation around topics such as climate policy, raise the stakes for democratic innovations such as climate assemblies. They are not only hoped to inform public deliberation, but also to act as a ‘deliberative bridge’ across ideological divides. Experimental studies, often using vignettes, have shown public legitimacy of DMPs to be affected by perceptions of process legitimacy and inclusivity, but also emphasised the importance of outcome favourability and heterogeneity in maxi-public responses to DMPs. This emphasises the challenge for innovations like climate assemblies to deliberatively bridge to diverse publics. Climate assemblies may be ‘preaching to the choir’, connecting to climate-concerned citizens but being dismissed or even stimulating ‘backfire effects’ amongst more sceptical publics. The media plays a key role as a connector between mini- and maxi-publics but few empirical studies explore the effects of real-life media coverage and framings. We present a survey experiment that tests how the perceived legitimacy of the Swedish Climate Assembly (SCA) is affected by contrasting news clips on Swedish Television, and/or factual text about the SCA. The clips provide a natural experiment based on actual media coverage. One clip emphasises the diversity of SCA members and their deliberative process, potentially supporting the discursive bridging role through procedural legitimacy. The other emphasises high ambitions of the SCA’s recommendations and could instead lead to backfire effects and low legitimacy amongst climate sceptical publics. A demographically representative sample of 3000 from a randomly-selected national panel were allocated into one of five treatment groups with combinations films and/or text information and compared with a control group who received no information. We test the effects on subsequent survey items capturing support for the SCA, percieved saliency, urgency and skepticism towards climate change, as well as support for climate policy measures, some of which are explicitly mentioned by the films and text treatment. We evaluate whether co-variates such as political attitudes, education, demographics, political trust and media habits explain heterogeneity in the responses to media. For example, whether typically skeptical respondents demonstrate a 'backfire effect', or can be persuaded of process-legitimacy by depictions of diverse recruitment and open deliberations. The data were collected in mid-2025 and will be analysed with regression models to test pre-registered hypotheses about the effects of film and text treatments on legitimacy perceptions, climate salience, skepticism and support for policies. We test heterogeneity through interaction terms. Finally we explore mediating effects of procedural perceptions of the SCA, such as that members included 'people like me', were competent, or received biased information. Our conclusions have implications for the potential and limitations of mini-publics as democratic bridges to counter polarization and politicised motivated reasoning in the maxi-public.