The Environmental Protection Agency (EPA) said it anticipated that the U.S. Supreme Court would ultimately rule that the nation’s district courts should decide lawsuits filed against an Obama-era rule over which waterbodies deserve protection under the Clean Water Act.

However, an energy industry attorney said the Trump administration could feel mounting pressure to rewrite the definition of what constitutes Waters of the United States (WOTUS), and that if previous lawsuits against the rule are any guide, such a move could see the roles of plaintiff and intervenor flipped in future legal challenges.

On Monday, the Supreme Court ruled unanimously that legal challenges to the controversial Clean Water Rule (CWR), such as National Association of Manufacturers v. Department of Defense et al., should be handled at the district court level. Last July, the EPA said it was moving forward with a two-step process to rescind the CWR, which it helped promulgate during the Obama years with the U.S. Army Corps of Engineers.

“The Trump administration saw this decision coming and put a plan in place to level the playing field and ensure certainty for states and the regulated community,” EPA spokeswoman Liz Bowman said Wednesday. “The Trump administration’s stay of the 2015 WOTUS rule will very likely be complete before any change in court jurisdiction can be finalized, or the Obama administration’s overreaching definition of WOTUS can be implemented.”

Media reports characterized the expected fallout from the Supreme Court ruling as one of impending chaos, especially sincea stay of the CWR first enacted by the Sixth District Court in Cincinnati in October 2015 is likely to be lifted, thereby technically putting the Obama-era rule into effect.

“There is ‘chaos’ in the sense that, rather than having these cases potentially brought to one of the 12 different circuit courts, they could now be brought to basically every single district court in the United States,” Baker & Hostetler LLP attorney Mark Barron told NGI’s Shale Daily on Wednesday. “Litigation over the Obama rule couldn’t get a lot messier now.”

Barron said the real issue is that the Trump administration “might feel pressure to try to get their rewriting of the rule done faster, so as to kind of avoid this litigation nightmare. That’s not going to be an easy task, obviously.

“When the Obama rule came out there were a couple of dozen lawsuits, and when the Trump administration rule comes out there will be a couple of dozen lawsuits. I just think some of the roles will be reversed on who is plaintiff and who is intervenor in some of these cases. The titles will be reversed, but there will be the same amount of lawsuits.”

Legal challenges to the CWR are “pretty fascinating,” he said, because the oil and gas industry and environmental groups both disliked the Obama-era rule, albeit for very different reasons.

“The industry basically said that [EPA] overstepped their jurisdiction, and environmental communities said it didn’t go far enough,” Barron said. “So I think you’re going to see lots of weird plaintiffs here, and what the Trump administration tries to set aside is going to be really interesting to follow.”

Environmental groups predicted that EPA ultimately could write a weaker rule to replace the CWR.

“The Trump administration should do what any responsible administration would do [and] implement the CWR wherever possible and vigorously defend it in the federal district courts,” said Clean Water Action spokeswoman Jennifer Peters. “But that is not what’s going to happen.” She said EPA Administrator Scott Pruitt and President Trump “have no intention of being responsible.

“Pruitt’s EPA is going to rush to finalize the legally questionable proposal to delay implementation of the CWR. This will leave streams, wetlands, and drinking water at risk of pollution and destruction while EPA finishes its shortsighted and dangerous endgame to replace the CWR with much weaker protections for our water.”