Why is it that in the limited elections held throughout the underdeveloped Arab world, parties seeking to implement Islamic law outperform those that call for greater redistribution? Drawing on the case of Egypt, in which an Islamist movement, the Muslim Brotherhood, has emerged as the country's principal opposition party, I argue that the reason for this outcome has less to do with the supposed cognitive, cultural, or informational advantages that accrue to Islamic political appeals, or with Islamists' allegedly Herculean efforts at social service provision, than with the nature of the authoritarian electoral ecologies within which they are embedded.

I argue that Egypt's electoral ecology renders most voters inaccessible to opposition parties, stunts party growth, and strains party cohesion. The Muslim Brotherhood performs well in this environment not because it commands the fealty of the masses—I find that the vote shares its candidates command, even controlling for electoral fraud, are relatively modest—but because it is better adapted than its rivals on the left and the right to cope with the challenges of thrown up by the system. The theory is tested with ethnographic, historical, and econometric evidence from in-depth field research in Egypt, and external validity is established by considering out-of-sample cases (within the Middle East and without).