Book excerpt: In the wake of the Arab Spring, newly empowered factions in Tunisia and Egypt vowed to work together to establish democracy. In Tunisia, political elites passed a new constitution, held parliamentary elections, and demonstrated the strength of their democracy with a peaceful transfer of power. Yet in Egypt, unity crumbled due to polarization among elites. Presenting a new theory of polarization under authoritarianism, the book reveals how polarization and the legacies of repression led to these substantially divergent political outcomes. The book documents polarization among the opposition in Tunisia and Egypt prior to the Arab Spring, tracing how different kinds of repression influenced the bonds between opposition groups.