In nearly all authoritarian regimes, democratization finds significant societal support and a number of organized opposition groups struggle for regime change. In some cases—such as in Iran in 1979— opposition groups are able to cooperate with one another and bring down authoritarianism. In others—such as the Assad regime in Syria—groups are not able to cooperate, and the ruler remains in place. Studies that apply cooperation theory on regimes predict that shared grievances about the current government and common interests in changing the existing regime foster cooperation among challengers. Yet, evidence suggests the contrary. This study examines the conditions under which diverse challengers, despite persistent divergence in their ideological preferences, are able to achieve a level of long-term cooperation that can transform the status quo. It uses the case studies of the Ottoman transition to constitutional monarchy (1876–1908) and the French transition to constitutional monarchy (1814–1830), paired according to the least similar systems design, in combination with network theory. Using this methodology, this study analyzes the effect of preferences on ideological issues (how the new regime should look like) and on strategic issues (how regime change should be carried out) to explain temporal dynamics of cooperation for regime change among challengers. This study conducts historiographical and archival work to identify the relevant actors and relevant issue dimensions and track preferences on these issues over time. It applies these findings on longitudinal network models (known as temporal exponential random graph models) to measure the extent to which preference alignment on an issue dimension, strategic or ideological, bring challengers to cooperate. Also, this study introduces two concepts. The first concept is “de-prioritization,” the process whereby challengers postpone the resolution of certain ideological disagreements to form sustainable cooperation against the regime. The second concept is “preference revision,” the process whereby challengers pragmatically replace their strategic preferences with more effective ones in response to past failures and environmental changes. Together these concepts emphasize that challengers become more likely to cooperate for regime change if they converge on a particular strategy of transition and sideline their ideological differences (if any). Convergence of preferences on strategic issues and the de-prioritization of ideological disagreements (if any) prepares the rise of a coherent oppositional coalition that is capable of signaling unity and coherence, hence potential to overthrow the regime if necessary or extract considerable concessions form an oppositional coalition that is capable of signaling unity and coherence, hence potential to overthrow the regime if necessary or extract considerable concessions. Findings suggest that without preference-revision and de-prioritization, challengers remain divided and heterogeneous in their approach, at best achieving temporary gains that are later reversed in the course of authoritarian retrenchment. This study further shows that the oppositional coalition tends to form around a core actor who has been committed to effective strategies and attracts others (peripheral actors) who agree with the core on the strategies but not necessarily on the ideologies. The implication of these findings are twofold: By taking dynamics of cooperation among challengers into account, we can distinguish between the cases where the regime is strong enough and takes on challengers and those where the government is weak but surviving because opposition groups are unable to assume power. Also, there is a link between the rise of an oppositional coalition and the likelihood of regime change happening.