The public influences government policy primarily through elections. Elections affect policy largely by determining which party controls the government. We show that a majority of the public supports policies to protect the environment. But the environment is rarely the most important issue for voters, and thus the environment usually does not have a large impact in elections. Moreover, there are increasingly large divisions between Democrats and Republicans – a situation that incentivizes politicians from both parties to embrace extreme positions. Democratic and Republican elected officials are increasingly polarized on environmental issues, with Democrats staking out much more liberal positions than Republicans in Congress. At the state level, Democratic control of legislatures and governorships leads to more stringent environmental policies. Democratic control of state government seems to have smaller effects, however, on environmental outcomes, such as air pollution emissions.