Environmental public opinion in U.S. states, 1973–2012

Partisan polarization of public opinion is a major trend in American environmental politics. While the national pattern is widely recognized, scholars know much less about the polarization of public opinion over time at the state level. This lack of knowledge is unfortunate because geographic variation in the polarization of opinion is essential for explaining the origins of partisan polarization and evaluating its consequences for policy. To fill the gap, the multilevel regression and poststratification technique is applied to provide credible estimates of state-level environmental public opinion for both Democrats and Republicans, 1973–2012. It appears that the growing partisan gap reflects increased pro-environmental opinion among Democrats across many states, whereas Republican state-level public opinion is converging toward a much lower baseline. Cross-state variation among both parties has decreased over time, contributing to greater partisan polarization in the aggregate. Changes in the sorting of voters in and out of political parties cannot explain these patterns of polarization.