The confirmation of Amy Coney Barrett to the Supreme Court could make it harder for future administrations to adapt laws that have been on the books for decades to meet emerging challenges such as climate change. That’s because Barrett’s confirmation would strengthen a conservative bloc of justices who take a narrow view of federal agency power — potentially spelling doom for efforts to write regulations to thwart greenhouse gas emissions and promote environmental justice.

“Barrett has made clear her disdain for federal agencies and the public protections they issue, which puts our ability to tackle climate change directly in her cross hairs,” said Gene Karpinski, president of the League of Conservation Voters. “And her positions on access to justice would make it even harder for communities of color to seek justice for repeated and targeted environmental harms.”

With Congress deadlocked on some of the biggest issues facing the U.S., from immigration to climate change, federal regulators have increasingly stepped in to fill the void. For instance, former President Barack Obama turned to the now 30-year-old Clean Air Act to write regulations curtailing greenhouse gas emissions from power plants.

But if Democrat Joe Biden wins election and tries to follow the same model of using “outdated statutes to address cutting-edge problems,” he may face a real challenge if Barrett is confirmed to the Supreme Court, said Tom Lorenzen, who leads the environment and natural resources practice at Crowell & Moring LLP. “If agencies do want to act, they’re going to need a more active Congress that is willing to legislate.”

Biden may be even more reliant on federal agencies to use existing laws to tackle weighty issues if Republicans retain control of the Senate, a scenario that would make it harder to enact new, tailor-made laws. Barrett’s three-year-tenure as a judge on the 7th Circuit Court of Appeals provides a limited view of her approach to federal regulation and environmental policy. And the previous opinions of Supreme Court nominees are not always a reliable indicator of how justices perform once installed on the high court. Still, legal experts say Barrett’s writings and rulings show her to be a textualist in the mold of the justice she once clerked for, the late Antonin Scalia — someone who favors a strict reading of the text of federal statutes.

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A Supreme Court that’s more skeptical of agency authority could look kindly on Trump administration rewrites of federal rules limiting the federal government’s reach when it comes to clean water oversight and required environmental analysis. With Barrett’s confirmation, the court is more likely to “embrace those more self-limited interpretations,” said Joe Goffman, executive director of Harvard Law School’s Environmental and Energy Law Program.