Democrats designed the climate law as a game-changer. Here’s how.

The Clean Air Act Enacted in 1970, with the birth of the environmental movement, it is the primary law outlining the EPA’s responsibilities to protect and regulate air quality. It was greatly expanded in 1990 to reduce other major environmental threats such as acid rain and urban smog.

The law defines greenhouse gases in some sections, but it does not explicitly direct the EPA to regulate carbon dioxide. Instead, it asks the agency more broadly to regulate pollutants that “endanger human health.” In 2007, Supreme Court, Massachusetts v. Environmental Protection Agency, No. 05-1120, Agency ordered To determine if carbon dioxide fits this description. In 2009, the Environmental Protection Agency I concluded that she did.

This conclusion implies that CO2 can be legally defined as a pollutant and regulator. The Obama and Biden administrations used this finding to justify regulations for gasoline vehicles and coal and gas-fired power plants, and several Supreme Court cases have subsequently upheld this authority.

However, because Congress had never directly addressed this issue before, challenges persisted. In West Virginia v. Environmental Protection Agency, No. 20-1530, the landmark ruling this year, conservative Supreme Court justices made clear that if lawmakers really wanted the government to move away from fossil fuels, they had to say so.

“One of the assumptions in the ruling was that Congress did not fully make clear that the EPA had a responsibility to address climate pollution from the energy sector,” said Vicki Patton, general counsel for the Environmental Defense Fund. “Well, now it’s very clear,” she said.

Some experts have played down the impact of the rulings. Jeff Holmstead, an energy attorney who worked for the Environmental Protection Agency during both Bush administrations, said there was little chance that legal efforts by some conservative groups to crack down on the government’s ability to regulate climate pollution would have prevailed anyway.