Who Speaks, Who Falls Silent: Strategic Climate Messaging by State Legislators on Facebook and X

Amid national gridlock on climate policy, state legislatures have become increasingly central to climate governance—yet we know little about how state legislators communicate climate issues online. Drawing on 6,177,988 social media posts from 6,353 legislators on Facebook and X (formerly Twitter) between 2020 and 2023, we fine-tune a large language model to classify climate-relevant content and stance. Among nearly 58,000 labeled posts between 2020 and 2021, 34,165 were supportive and 11,573 opposing, with clear variation across platforms. Legislators with more extreme ideological positions are more likely to discuss climate issues, and electoral competitiveness increases climate discourse on X but not Facebook. While local economic dependence explains some opposition, legislators’ messaging is more powerfully shaped by interest group pressure. These groups exert strategic, platform-specific influence—silencing supportive voices from liberal legislators on X and promoting opposition through campaign donations. Our findings underscore the need to examine not just ideology and platform, but also how interest groups strategically shape legislators’ climate messaging across different online environments.