The Supreme Court temporarily cleared the way on Wednesday for the Environmental Protection Agency to limit carbon emissions by power plants.
The decision was a victory for the Biden administration, which has been stymied in the courts over its efforts to protect the environment. In June, the Supreme Court temporarily paused an E.P.A. plan to curb air pollution that drifts across state lines. It has also constrained the agency's ability to limit water pollution and factors that lead to climate change.
The ruling did not include the court's reasoning, which is typical in emergency applications. But Justice Clarence Thomas noted that he would have blocked the emissions rule. The court's order also indicated that Justice Samuel A. Alito Jr. did not participate in the deliberations, although no reason was given.
In a brief statement, Justice Brett M. Kavanaugh, joined by Justice Neil M. Gorsuch, said that while he agreed with the court's decision to allow the emissions rule to go into effect, he believed that some of the Republican-led challenges "have shown a strong likelihood of success on the merits."
Still, Justice Kavanaugh said that a lower court would have sufficient time to review the case given that the power plants would not have to start work to comply with the rule until June 2025.
The order was provisional while a challenge moved forward in the courts.
Since late July, the Supreme Court has fielded a series of challenges to a major regulation enacted by the E.P.A., including from a group of states led by conservatives, along with power plant companies and other industry players.
The regulation, enacted in April, seeks to eliminate pollution from coal, which emits more carbon dioxide than any other fossil fuel. The move is part of the Biden administration's promise to curb pollution from such emissions by 2050.
Under the rule, coal- and gas-fired power plants slated to operate long-term would have to capture up to 90 percent of their emissions by 2032. The requirements are less strict for power plants scheduled to close in the coming years.
The more than two dozen states challenging the regulation argue that the federal government has failed to prove that the techniques used to control emissions would curtail them to the degree that the government is seeking.
The challenge is currently pending in the U.S. Court of Appeals for the District of Columbia Circuit. In July, a three-judge panel refused a request by the conservative-led states to stop the E.P.A. rule from going into effect while the court case continued, prompting the states and other groups to ask the Supreme Court to step in.
In its decision, the appeals court panel wrote that there was no need to pause the E.P.A. rule from going into effect while litigation continued because the case would proceed quickly and the federal government's compliance deadlines were years from now, in 2030 or 2032.
The Biden administration announced the rule in April as part of a broader effort at limiting pollution from power plants. Several Republican-led states, including West Virginia, Indiana, Alabama and Alaska, challenged the regulation the same day.
In their emergency application, the states accused the agency of being "driven by a distaste for fossil-fuel fired facilities," and seeking to "force coal-fired plants to close and shift over to E.P.A.'s preferred methods of power generation."
The states argued that the E.P.A. had exceeded its authority by creating the rule without specific congressional approval, and called the rule "an unlawful and ill-advised attempt to restructure the entire power industry." They said the agency's rules set "impossible-to-meet standards for regulated facilities, stripping away the states' discretion to patch up the damage and ultimately pushing regulated sources into early retirements."
The states claimed that the new rule would also cause "serious immediate harms" by forcing power plants to make determinations about whether to close down or to "start spending large sums" to ensure they could meet compliance deadlines.
In recent years, they said, the E.P.A. followed a similar pattern. "Faced with this recognizable story," they continued, the three-judge panel should temporarily halt the environmental regulation given the damaging implications for the future of the coal industry.
The justices should "step in and hit pause so that the fossil-fuel-fired power industry isn't pushed out of existence while this case wends its way through the judicial-review process," they wrote.
In its brief, the Biden administration argued that the E.P.A. had acted within its authority in setting emission limits and that it had determined that the best approach was 90 percent carbon capture. The technology uses chemical solvents to remove carbon dioxide from the exhaust stream of a power plant, permanently storing it underground.
The Biden administration contended that the challengers did not take issue with how the E.P.A. had interpreted the Clean Air Act, but objected to the agency's "technical and scientific judgments regarding the dependability, feasibility and cost of carbon capture."
Those critics, Solicitor General Elizabeth B. Prelogar wrote, "largely ignore the hundreds of pages of analysis" by the E.P.A.
Although the challengers portrayed carbon capture as "an untested, futuristic technology," Ms. Prelogar added, the agency found that its benefits had been "adequately demonstrated."
The dispute was the latest bid by Republican-led states to undercut the Biden administration's ambitious climate agenda. The challenge carries similarities to a case the Supreme Court considered in the term that ended in July. Three states, Ohio, Indiana and West Virginia joined with industry groups to challenge an E.P.A. proposal aimed at limiting the flow of air pollution across state lines, asking the Supreme Court to intervene even as the challenge continued to be litigated in lower courts.
In June, the justices paused the proposal, known as the "good neighbor" plan, which requires factories and power plants in the West and Midwest to cut ozone pollution that makes its way into Eastern states.
In recent years, the court has proved receptive to efforts that chip away at the power of the E.P.A., thwarting various attempts by Mr. Biden to fight pollution.
In May 2023, it curbed the agency's authority to regulate millions of acres of wetlands. And in June 2022, it limited its ability to regulate carbon emissions from power plants, a significant setback to Mr. Biden's goal of cutting greenhouse gas emissions nearly in half by the end of the decade.
Coral Davenport contributed reporting.