Highest courts cannot enforce decisions themselves but need to rely on external actors. This is why scholarship argues that courts seek to mobilize public opinion to hold governments accountable to judicial decisions. However, it remains unclear how judges can successfully communicate their decisions’ content precisely to encourage a desired action. I argue that citizens neither carefully read nor fully comprehend judicial decisions. Instead, the court mobilizes mediators to communicate a decision and activate public opinion.

I design a formal model including external actors as mediators, the court, and the government. Mediators activate the public to impose costs on a government if it not complies to a judicial decision. Thus, the presence of mediators defines the strategic choices that judges make in opinion-writing. When courts weight their policy preferences higher than the potential costs of non-compliance, then they activate external actors as mediators by addressing them to a greater extent in their opinion-writing. Analyses of Senate decisions published by the German Federal Constitutional Court since 1998 provide empirical support for this equilibrium strategy derived from my model. This has major implications for our understanding of how courts activate public opinion through mediating actors to communicate and enforce their decisions. Further, the model provides a plausible explanation for why non-governmental actors pay the costs to approach the court; namely, to pursue their own agenda.