On Thursday, the Environmental Protection Agency is expected to restore risk-finding, which underpins the ability of the US to regulate the greenhouse gases that cause climate change. The rollback, the result of more than 15 years of work from right-wing special interest groups, represents the most aggressive move against US climate regulation to date—and will herald a long battle that will almost certainly end up before the Supreme Court.

The move could also create significant legal and regulatory uncertainty for a wide range of industries, from oil companies fighting state and local climate lawsuits to auto companies trying to plan production of new models amid an ongoing legal battle.

“I don’t see any plan, any strategy, any end game,” said Pat Parenteau, a professor of environmental law at the University of Vermont. “I don’t see anything from this administration, just do everything you can. You can print that.”

The Clean Air Act mandates that the EPA regulate any type of air pollution that poses a risk to public health and welfare. The risk finding was a 2009 ruling that created a scientific and legal basis for regulating greenhouse gases under the Clean Air Act. This finding has been the basis of every climate-based regulation the agency has issued since, from restrictions on power plants to emissions standards for cars.

The original finding was ordered in a 2007 Supreme Court decision, Massachusetts v. EPAin a lawsuit brought by the state against the Bush administration, challenging it for not taking action to control greenhouse gas emissions from automobiles. The Supreme Court ruled that greenhouse gases should be regulated under the Clean Air Act.

Even before risk-taking officially existed, it was already a political football for right-wing interests. Following the Supreme Court’s decision, the Bush-era EPA sent an email to the White House linking six greenhouse gases to climate change and detailing a wide variety of effects on public health and the environment. However, the White House refused to open the email to acknowledge the science and the findings, kicking the can down the road for nearly two years until the email was completed. released in 2009 under the Obama administration. Right-wing groups, including the Heritage Foundation, the group behind the Project 2025 plan, have previously vocal critic EPA’s judgment and actions on greenhouse gases for nearly two decades. (As The New York Times reported on Monday, the Heritage Foundation campaign funds in 2022 to help create regulatory documents that enable the recovery of risk finding.)

Finding danger has proven to be very difficult for these attack groups. Two of Trump’s first EPA administrators declined to challenge the search while they were in office, despite pressure from ideologues inside and outside that administration.

This reluctance is thanks in part to businesses that supported the original EPA decision. “The industry is generally in favor of stability in this space and having the EPA maintain regulatory authority,” said Meghan Greenfield, a former senior adviser to the EPA. “Risk finding serves this important purpose of leveling the playing field and recognizing EPA’s authority.”

A draft version The rollback issued this summer contained several arguments aimed at undermining the finding, including making the case that because greenhouse gas emissions are global, they should not be regulated under the Clean Air Act.

“The proposal is pretty much throwing spaghetti at the wall,” said Rachel Cleetus, a senior policy director at the Union of Concerned Scientists. “There are all kinds of arguments, all of them without merit — Clean Air Act arguments, science arguments, cost arguments.”