The Arab Spring revolutions in Egypt and Syria were significant disruptions to the Middle East and North Africa region. Their continually evolving consequences present the United States with immense challenges to regional and international stability. Responses to the Arab Spring demand a nuanced appreciation of the sources of fragility and causes of revolution that toppled the Mubarak regime and continue to embattle the Assad regime. Crucially, the individual histories of Egypt and Syria indicate that repressive authoritarian regimes were unresponsive to and disconnected from the broad mass of their populations and failed to meet the basic expectations of their citizenry. Several stressors amplified the regimes fragility, namely increasing radical Islamism, the capacity for social mobilization through Internet and communication technologies, long-term demographic pressures, andcruciallyclimate-driven pressures. The fact that the US military is likely to deepen its response to the Arab Spring and similar instability indicates that studying the origins of these crises is indispensable.