In the five years since the collapse of federal cap-and-trade legislation, state governments across the U.S. have been pursuing their own initiatives on climate change. “So now the Environmental Protection Agency (EPA) has embraced the bottom-up ethos,” writes Muro, a senior fellow and director of policy at the Brookings Institution’s Metropolitan Policy Program. The EPA and the White House “have proposed a carbon scheme that recognizes that states have been innovating, places states at the centre of the emissions push, and gives them the maximum amount of flexibility to limit carbon pollution.”