On Friday, a federal judge in Montana District Court dealt the Trump Administration another setback pertaining to leasing out federal lands for fossil fuel extraction.

In an order (PDF), the judge said that the US Department of the Interior (DOI) had to conduct a review of the impacts of its decision to lease federal land for coal mining under the National Environmental Policy Act (NEPA).

Under the Obama Administration, the DOI placed a moratorium on leasing federal land out for coal mining. The move was expected to have significant impact on greenhouse gas emissions: according to the Friday order, "the federal coal program, as of 2014, stands responsible for an estimated eleven percent of total United States greenhouse gas emissions." Coal use has tumbled in the five years since 2014 , but it still remains a significant fuel source in many parts of the country.

In 2017, however, Trump Administration Interior Secretary Ryan Zinke issued an order to remove the coal leasing moratorium for federal lands. The government began processing requests for leases, and several states as well as the Northern Cheyenne Tribe sued the DOI in hopes of stopping it from granting 20-year leases that would create more environmental disruption and greenhouse gas emissions.

The DOI argued that it didn't have to open up any time-consuming NEPA-related reviews because "the Zinke Order did not constitute a major federal action that triggered NEPA." Instead, the DOI said its rollback of the moratorium was a mere "policy shift."

But the Northern Cheyenne Tribe said that its only recourse to fight the moratorium rollback was through procedures prescribed under NEPA, and the tribe argued that it is entitled to a formal consultation about the environmental impacts of re-opening coal leasing on federal lands.

The judge declined to give an opinion on whether the Obama-era moratorium should stand, but requiring an environmental review of coal mining in advance of granting new leases will likely slow the Trump administration's attempts to prop up coal.

The setback is another major one for the Trump administration, after a federal judge in Alaska recently ruled that President Trump couldn't reopen waters that former President Obama closed to offshore oil drilling in the Arctic. Based on a quirk of the 1953 Outer Continental Shelf Lands Act, the judge said that reopening indefinitely closed waters appears to require Congressional approval and can't be done with unilateral Presidential approval.

On Monday morning, the Institute for Policy Integrity praised the judge's order requiring the DOI to complete reviews of coal leasing under NEPA. “When it lifted the moratorium on coal leasing in 2017, Interior failed to do any environmental analysis of its major action, even while federal coal accounts for 40% of the nation’s total and coal is the most polluting of our energy sources," said a statement issued by the institute. "Interior must conduct an environmental review of the federal coal leasing program because it lifted the moratorium, relaunching a major program that emits greenhouse gases and other air pollutants."