The fate of the regimes in the Arab world after 2011 protests has prompted scholars to ask how and whether different authoritarian institutions affect mass protest. Why did Mubarak fall, but not King Mohammed VI? Are the paths to regime change different in monarchies? The literature on regime change largely focuses on the shift from authoritarian regimes to democratic ones, with few distinctions made between monarchies and authoritarian republics. This paper argues that monarchies have a unique institutional feature that other types of authoritarian regimes lack: they can democratize without destabilizing the leadership by becoming a constitutional monarchy. Constitutional monarchy is desirable because it offers both democracy and stability. This possible outcome alters the calculus of regime opponents by providing an additional option unavailable to opposition forces in other kinds of authoritarian regimes. The promise of constitutional monarchy complicates coordination among regime opponents and affecting the kinds of claims they make. Arab kings did not survive the Arab Spring because they were more legitimate, smarter, or because they offered more meaningful reforms, I argue. Nor were kings invulnerable; monarchies can and do end through collective action. But the calculus that protestors face differs in monarchies. I illustrate this argument through a study of protest in Morocco during the Arab Spring and I propose ways to test it using historical data and large-N cross-national comparisons