How does regime change affect the risk of militarized disputes? Within the democratic peace literature, there is disagreement over whether it is democratization, autocratization, political dissimilarity or political instability that is particularly perilous. I distinguish four perspectives from this literature and test their attendant hypotheses on a dataset of conflict episodes within enduring rivalry from 1816 to 2001 using survival analysis. I find that both democratization and autocratization reduce the hazard of dispute recurrence in enduring rivalries. After controlling for selection bias, the effect of democratization was robust whereas the effect of autocratization was not. Democratization also has the additional property of terminating rivalries; autocratization does not. Together, the results imply that democratization is better at promoting a transition from rivalry to peaceful relations than is the autocratization of a rivalry dyad.