Jurisdictional REDD+ is widely promoted as a mechanism to align forest conservation, and climate mitigation, through standardized readiness frameworks and multilevel governance, yet a persistent dilemma remains: how can politically divergent subnational states converge on the same international climate finance outcomes? This study addresses that question by comparing two contrasting Brazilian Amazon states that both secured funding under the REDD+ Early Movers (REM) program. Methodologically, the research employs comparative process tracing, drawing on 287 documents and 74 semi-structured interviews, and applies Van Evera's evidence tests to assess the strength of causal explanations for program approval. The results reveal five necessary conditions for REM financing, formal compliance with REDD+ Readiness requirements was neither necessary nor sufficient for success; instead, informal arrangements, historical political trajectories, paradiplomatic networks, and multilevel coalitions among social actors played a decisive role. These findings lead to the conclusion that jurisdictional REDD+ operates less as a hierarchical implementation of institutional models and more as a polycentric governance process emerging from dynamic interactions across governance scales. By reconstructing the causal mechanisms that link international climate finance to subnational forest politics, this study advances theoretical debates on climate finance while offering practical insights for policy design in heterogeneous political contexts.