Had the court rejected Mr. Trump’s request and upheld the Clean Power Plan, it would have made it far more difficult for Mr. Pruitt to roll back the rule.
“This ruling is important, because it means it will now be easier for the Trump E.P.A. to revoke or revise the Clean Power Plan,” said Jeff Holmstead, a lawyer with the firm Bracewell, which represents many of the fossil fuel companies suing to overturn the rule. “At the very least, it means it will take less time.”
The legal hold will have little practical impact, however, upon the nation’s energy economy and coal industry. The climate change rule has never been formally put in place, after the Supreme Court last year said that states did not have to comply until all litigation had been resolved.
But the ruling comes as the environmental movement is galvanized against what many advocates for climate action have called a concerted assault on environmental protections by Mr. Trump. On Saturday, thousands of demonstrators are expected to march in Washington and across the country to protest those actions.
“This further delay by the court comes even as hundreds of thousands around the country prepare to march tomorrow for the climate protection that polls show an overwhelming majority of Americans strongly support,” said Paul Bledsoe, a former climate adviser for the Clinton administration who is now a lecturer at the Center for Environmental Policy of American University. “Coming on top of the unprecedented Supreme Court stay last year, it gives the appearance to average citizens that the courts are standing with the far-right wing against sensible climate action.”