U.S. political polarization is at a high point since the Civil War, and is a significant barrier to coordinated national action addressing climate change. To examine where common ground may exist, here we comprehensively review and characterize successes and failures of recent state-level decarbonization legislation, focusing especially on bipartisanship. We analyze 418 major state-government-enacted bills and 450 failed bills from 2015 to 2020, as well as the political contexts in which they were passed or defeated. We use bivariate analyses and regressions to explore correlations and partial correlations between the policy characteristics and political contexts of bills, and their passage or failure, their bipartisanship, and vote shares they received. Key results include (i) nearly one-third of these state-level decarbonization bills were passed by Republican-controlled governments. (ii) Bipartisan or Republican co-sponsors disproportionately passed financial incentives for renewable energy, and legislation that expands consumer or business choices in context of decarbonization goals; Democrat-only co-sponsors disproportionately passed bills that restricted consumer and business choice, such as mandatory Renewable Energy and Efficiency Portfolio Standards (REEPS) and emissions standards. (iii) Bipartisan bills were disproportionately proposed in “divided” states, did not restrict consumer and business choice, had environmental justice components framed economically, and lacked environmental justice components framed either using academic social-justice jargon or non-neutrally with respect to immutable characteristics such as race. (iv) Bills that expand consumer or business choice were disproportionately enacted. Though climate change is a polarized issue, our results provide tangible insights for future bipartisan successes. Supplementary Information The online version contains supplementary material available at 10.1007/s10584-022-03335-w.

Concerns about polarization and the difficulty moderate candidates have in winning primary elections have driven several electoral reform efforts in recent decades. In this article, we leverage reforms prior to the 2022 elections in Alaska to assess whether the top-four primary is likely to help moderate candidates succeed. We evaluate three mechanisms by which the top-four might help moderates: by allowing them to advance from the primary and compete for votes from the more moderate general electorate, by changing the composition of the primary electorate and/or by facilitating crossover voting during the primary. Our analysis suggests that the top-four primary creates opportunities for cross-party voting that can enhance the electoral prospects of moderate candidates.

Political polarization is at a high point in recent U.S. history and may now be the most significant barrier to coordinated national action addressing climate change. Studies of intergroup conflict suggest that collaborations pursuing shared goals can reduce polarization (and also advance the goals). In this spirit, I comprehensively review and characterize successes and failures of state-level climate legislation, focusing on opportunities for bipartisanship. I analyze 356 major state government enacted bills and 372 failed bills--aimed at decarbonization--from 2015 to 2020, as well as the political contexts in which they were passed or defeated. I use bivariate analyses, regressions, and decision trees to explore correlations and partial correlations between the policy characteristics and political contexts of bills, and their passage or failure, their bipartisanship, and the vote shares they received. Key results include: (i) Roughly one third of these state-level decarbonization bills were passed by Republican-controlled governments. (ii) Bipartisan or Republican co-sponsors disproportionately passed voluntary Property Assessed Clean Energy (PACE) programs, solar incentives, renewable energy portfolio goals, and transportation electrification; Democrat-only sponsors disproportionately passed mandatory Renewable Portfolio Standards (RPS) and emissions standards. (iii) Bills proposed in "purple" states, and those lacking explicit environmental justice components, were disproportionately enacted and bipartisan. Concerning broader framing components, bills that expand consumer or business choice and/or include financial incentives are enacted more often than those that restrict choice. Though climate change is a polarized issue, my results provide tangible insights for future bipartisan successes.