Americans across the political spectrum increasingly believed democracy was in danger. Yet many still supported candidates who undermined democratic norms and expressed hostility toward people from the other party.

This growing tolerance for undemocratic behavior—paired with deepening social distrust and political violence—was fueled by distorted perceptions, algorithmic amplification, and a lack of evidence-based tools to change hearts and minds.

While hundreds of civic groups were working to bridge divides, few interventions had been tested at scale with rigorous, comparable data.

To meet this challenge, the project crowd-sourced 252 ideas from scholars and civic practitioners across 17 countries, ultimately selecting 25 promising interventions for a megastudy. Each intervention was tested using the same randomized, controlled experimental design, allowing for direct comparison of outcomes. Treatments included video, text, games, and chatbot interactions—covering strategies like correcting misperceptions, fostering empathy, reinforcing shared identities, and amplifying democratic norms.

Every treatment was evaluated on eight measures of democratic health, including support for political violence, willingness to back undemocratic candidates, and behavioral indicators like money-sharing in real-stakes games. The study didn't just ask what moved attitudes—it asked what stuck. Ten interventions were followed up two weeks later to assess durability.

This side-by-side structure—applied at massive scale—represented a new gold standard in testing civic interventions.

Partisan hate and institutional mistrust didn't just corrode politics—they shaped how people treated one another in everyday life. As polarization escalated, so did threats to civil discourse, election integrity, and peaceful pluralism. But this study proved something powerful: these attitudes weren't fixed. With the right tools, animosity could be reduced, false assumptions corrected, and trust rebuilt—sometimes in just minutes.

By revealing which strategies meaningfully shifted attitudes—and which backfired—the Strengthening Democracy Challenge offered a roadmap for everyone working to reduce division, from tech platforms and policymakers to teachers and grassroots leaders.

Key Results: 23 of 25 interventions reduced partisan animosity—some by the equivalent of 8 years of polarization growth. 6 treatments reduced support for undemocratic practices, and 5 reduced support for partisan violence. Most effective strategies: Humanizing stories and personal narratives Emphasizing shared American identity Correcting exaggerated misperceptions of the other side Pro-democracy cues from trusted political elites Durability: Several treatments sustained impact two weeks later—especially those rooted in shared identity and emotional resonance.