SCOTUS doesn’t want to discuss WOTUS.

In a setback for the Trump administration, the U.S. Supreme Court ruled unanimously on Monday that the nation’s district courts, not the appellate court system, should decide a legal challenge over which waterbodies deserve protection under the federal Clean Water Act.

At issue is the definition of what constitutes Waters of the United States (WOTUS). Last July, the Environmental Protection Agency (EPA) said it was moving forward with a two-step process to rescind the controversial Clean Water Rule (CWR), which it helped promulgate during the Obama years with the Army Corps of Engineers. The Trump administration had appealed to the Supreme Court in hopes of accelerating the rescission process.

But on Monday, Justice Sonia Sotomayor opined that “even if the court might draft the statute differently, Congress made clear that rules like the WOTUS rule must be reviewed first in federal district courts…

“The government argues that immediate court-of-appeals review facilitates quick and orderly resolution of disputes about the WOTUS rule. We acknowledge that routing WOTUS rule challenges directly to the courts of appeals may improve judicial efficiency…But efficiency was not Congress’ only consideration. Had Congress wanted to prioritize efficiency, it could have authorized direct circuit-court review of all nationally applicable regulations, as it did under the Clean Air Act.”

The case is National Association of Manufacturers (NAM) v. Department of Defense et al.

Linda Kelly, NAM’s senior vice president and general counsel, called the ruling “a win for manufacturers” on Monday.

“We are pleased that the Supreme Court decided to help clarify what the law requires by taking action on this case,” Kelly said. “As manufacturers, we understand the importance of responsibly managing water resources and have been working to protect clean water for decades. That’s why we have been asking for a clear rule from the EPA and the Army Corps that empowers everyone to join in protecting our waters.”

EPA’s two-step plan involved initiating a public rulemaking to rescind the CWR and revert to laws governing water protection that were first enacted in 1986. The agency would then promulgate a revised definition of WOTUS. The Sixth District Court in Cincinnati issued a stay and blocked it from being implemented in October 2015.

Last February, President Trump signed an executive order instructing EPA and the Army Corps to review the CWR. Although the order did not repeal the CWR outright, it kicked off a review and rulemaking process that was expected to extend into 2018.

According to EPA, the proposed WOTUS definition would include all territorial seas, interstate waters and wetlands and all waters that are currently being used — or which were used in the past or which may be susceptible for use in interstate or foreign commerce — including all waters subject to the ebb and flow of the tide. It also includes certain impoundments, tributaries and adjacent waters, including wetlands.

Opponents of the rule, including the oil and gas industry, worry that it is so broad that it could be used to include ditches and ruts in dirt roads that capture rainwater.

Republicans in Congress have been working on a second track to abolish the CWR. Earlier this month, the House Appropriations Committee included a policy rider in the energy and water spending bill for fiscal year 2018 that authorizes the EPA and the Army Corps to withdraw the rule. House Democrats then attempted to add an amendment to remove the policy rider, but it failed along party lines.