In 2011, the Arab Spring revolutionary movements that erupted across the Middle East galvanized supporters in the diaspora to work collectively for regime change and relief at home. Existing theories argue that diasporas residing in democratic states possess the requisite political opportunities and resources to mobilize on behalf of their home-countries and intervene in significant ways. However, this explanation cannot account for why diaspora movements only emerge and play a role in home-country crises under certain conditions. This dissertation therefore investigates 1) how members of the Libyan, Syrian, and Yemeni diasporas in the US and Great Britain mobilized to support the 2011 uprisings, and asks 2) why the pace of their public emergence as regime opponents, their degree of intra-movement solidarity, the strength of their roles in the revolutions, and the short-term outcomes of their efforts varied significantly by national group. In order to explain this variation, this study analyzes three sets of data using grounded and process-tracing methods: 240 original interviews; ethnographic participant observations of Syrian-American pro-revolution events; and secondary sources on the diasporas and the revolutions.

The findings demonstrate that diaspora mobilization dynamics are shaped by multi-level and relational factors that not only include political opportunities in the host-country, but also conditions in and diasporas’ relations with relevant actors in the home-country—including sending-state regimes and opposition movements—and relevant third-parties, such as journalists and international institutions. I find that quotidian disruptions to any one of these conditions and relations produce corresponding changes in the strength and longevity of diasporas’ collective actions. This study also demonstrates that activists overcome obstacles to transnational mobilization posed by hostile external conditions when they divert resources to establish full-time formal advocacy organizations. Though this strategic adaptation constrains their tactics, movements that do not make this adaptation are likely to die off. The establishment of a transnational organizational field also improves the capacity of diasporas to pursue rights and recognition in both the home- and host-countries over time. I conclude by discussing the theoretical implications of these findings for the study of social movements, diasporas, and conflict.