There were large differences in the responses of Arab dictators to the Arab Spring protests. To understand these differences, I present a stylized model of how a dictator responds to mass protests for democratization in a polarized country with two ethnic or religious groups. In this model, the dictator's response crucially depends on oil revenues and his affiliation to either the majority or the minority group. I document that the model's predictions are consistent with the observed differences in the Arab dictators' responses. Hence, ethnic politics and religious divides may play an important role in political transitions and regime changes.