This fascinating paper explores protest diffusion in the 2011 Arab Spring:
This paper examines how protests spread across countries in the 2011 Arab Spring. Based on the diffusion literature, we form hypotheses about the factors that influence the transmission of protests across borders. To test the hypotheses, we use an events data set measuring media reports of protests, government reforms, and acts of repression on a daily basis by country. We show that the strength of the protest movement in one country is significantly affected by protest activities in other countries over the previous 1 or 2 weeks and that protests were more likely to spread between countries that had high levels of bilateral trade. When we examine periods longer than 2 weeks, we find that protests spread across borders only when they were successful in pressing Arab governments into enacting reforms and when the protests did not lead to government reprisals. In all our models, government repression in one country significantly stifled protests in other countries. Each country was thus significantly affected by the choices that governments in other Arab League nations made, and this interdependence meant that governments had incentives to cooperate with each other in their responses to the Arab Spring protests.