Understanding the effect of international social ties on domestic ideological polarization is challenging because the counterfactual—what would have happened without cross-border links—cannot be directly observed. This study uses a new statistical approach to estimate that missing comparison and separate polarization into domestic and transnational components following the Arab Uprisings.

📊 Twitter Data From Egypt and Tunisia in 2013

A dataset of Twitter accounts in Egypt and Tunisia was assembled for the critical year 2013, when the Egyptian military overthrew Islamist President Mohamed Morsi.

🔬 A Bayesian Item-Response Approach to Isolate Cross-Border Effects

A Bayesian item-response theory model is applied to disaggregate observed polarization into domestic and transnational components, providing an estimate of polarization both with and without international social connections.

📈 Key Findings

• Following the 2013 coup, retweets among Egyptian ideological allies increased by 50% each day, while cross-ideological retweets decreased by 25%.
• Tunisian Twitter communities also showed stronger intragroup retweeting after the coup, though at lower levels than in Egypt.
• Counterintuitively, the model indicates that the additional polarization in Tunisia after the coup appears to have dampened further polarization among Islamists in Egypt.

❗️ Why It Matters

These results show that transnational social ties can both amplify and attenuate domestic polarization in moments of political crisis. Identifying and measuring those cross-border effects requires methods that separate domestic dynamics from international influence—an essential consideration for scholars and policymakers studying polarization around uprisings and coups.