Public comments closed earlier this week on the Environmental Protection Agency’s (EPA) and the Army Corps.’ proposed replacement rule designed to clarify which waterways in the country are subject to Clean Water Act (CWA) jurisdiction. While supporters of the new rule urged an even narrower approach, opponents attacked it as an abdication of environmental responsibility.

The limit on the federal government’s authority to regulate the pollution of wetlands and tributaries that run into the country’s largest rivers would be a major win for builders, farmers, coal miners, and frackers. Fifteen attorneys general (AGs), however, vehemently oppose the proposed rule as contrary to the Clean Water Act’s objective of restoring the country’s waterways. They allege that the proposed rule would end federal oversight of fifteen percent of streams and more than half of the country’s wetlands and would violate the Administrative Procedure Act.

The Supreme Court has already weighed in on this issue, ruling that the appropriate standard requires that a regulated body of water must have a “significant nexus” with other, larger waterways. Based on the AGs’ comments which accuse the Trump administration as having “abandoned both the governing ‘significant nexus’ test for defining waters” and “their prior scientific findings under the test,” however, it appears inevitable that this debate will have to be resolved by the courts.