This concluding chapter synthesizes findings from comparative analysis of subnational governments across the United States, Canada, Germany, Spain, and the UK to assess whether Under2 Coalition founding members demonstrate greater climate leadership than later joiners. The analysis reveals mixed support for propositions linking reputational incentives to climate policy effort: California, Baden-Württemberg, and Catalonia exhibited sustained leadership consistent with theoretical expectations, while cases like Ontario and Scotland complicate straightforward temporal patterns. Beyond membership timing, constitutional arrangements, partisan composition, economic context, and institutional capacity emerge as critical mediating factors. The study identifies four leadership types—structural, cognitive, entrepreneurial, and exemplary—manifested across jurisdictions, while recognizing followership as strategically significant, with some actors using it as a calculated pathway toward eventual leadership. Key limitations include conceptual simplification of leadership/followership dynamics, exclusive focus on high-income democracies, and case selection biased toward Under2 Coalition members. The chapter alludes to future research which could expand geographic scope to Latin America and other regions, develop more nuanced theoretical frameworks integrating multilevel governance and network effects, and incorporate non-member jurisdictions for comprehensive comparison.