Will the Arab Spring lead to long-lasting democratic change? To explore this question, I examine the determinants of the Arab world’s democratic deficit in 2010. I find that the percentage of a country’s landmass that was conquered by Arab armies following the death of the prophet Muhammad statistically accounts for this deficit. Using history as a guide, I hypothesize that this pattern reflects the long-run influence of control structures developed under Islamic empires in the premodern era and find that the available evidence is consistent with this interpretation. I also investigate the determinants of the recent uprisings. Taken in unison, the results cast doubt on claims that the Arab-Israeli conflict or Arab culture or Muslim theology is a systematic obstacle to democratic change in the region and point instead to the legacy of the region’s historical institutional framework.