Abstract
When President Biden won the 2020 election and Democrats gained control of Congress, a climate policy window opened. Many voters, activists, and lawmakers wondered: after 10 years of inaction, would the United States finally pass a federal climate law? This article explains the passage of the Inflation Reduction Act (IRA) in 2022, the single largest climate and clean energy investment in American history. Our research draws on participant observation, interviews, primary and secondary sources. We construct a five-year political history from 2018, identifying key points of departure from Congress’s attempt to pass the Waxman-Markey bill during the Obama administration. We argue that the IRA passed because activist outsiders used scientific target-setting and the Democratic Presidential primary to put climate on the political agenda. They built stronger coalitions with tighter coordination. Congress chose to pass the bill through budget reconciliation, allowing Democrats to sidestep the filibuster, and empowering their most conservative member. Finally, time constraints and outside pressure led key negotiators to secretly finalize the deal without opponents weighing in. We briefly describe implementation and the second Trump administration’s attempts to repeal the law. Our conclusions about activist strategy, legislative compromise, and policy durability have implications for policymakers, advocates, and social scientists working on climate politics.