This article analyses the ongoing role of climate change litigation as part of transnational efforts to address the problem. The article begins by examining the impacts of the litigation thus far, and mapping its ongoing role. It considers the litigation's effect on governmental regulatory decision-making, corporate behavior, and public understanding of the problem. The article then builds upon this examination by exploring climate litigation's influence upon particular actors at different levels of government over time. It argues that climate change litigation provides a valuable complement to other law and policy efforts because it fosters needed interaction across levels of government and different time periods. The article next engages these scalar dynamics more deeply through a diagonal federalism approach, which focuses on the disputes' simultaneous vertical and horizontal elements. It applies a taxonomy of diagonal regulatory approaches to two examples of climate change litigation stemming from the US Clean Air Act, and considers the implications of that analysis for understanding the cases' regulatory role. The article concludes by reflecting upon the continuing importance of this litigation in influencing the behavior of key public and private actors.