The Paris Agreement is in trouble. Here we assess the potential for climate leaders to bring the global climate regime back on track by developing a strategic understanding of followership. In other words, leaders need to know how to encourage other actors to follow them. We develop a typology of follower types—Enthusiasts, Pliables, Reluctants, and Hard Nuts—distinguished based on motivation and capacity. We identify the scope for a participation cascade based on the distribution of follower types. We argue that achieving a participation cascade may be more likely if leaders appreciate three insights from theories of collective action. First, break down the climate mitigation problem into smaller, more manageable challenges, such as sectoral approaches. Second, prioritize major emitters and areas with high mitigation potential and politically feasible action. Finally, emphasize co-benefits to potential followers. Together, the strategies can help reduce the number of Hard Nut cases by making the cost/benefit calculus more attractive to prospective followers. Climate summits have become festivals at which leaders talk about leadership. But leadership doesn’t matter without followership. And that’s the problem in addressing the climate crisis. There aren’t enough followers. —David G. Victor (2019a)