This article was originally published in Law360 on Oct. 7, 2022.

On Oct. 3, the U.S. Supreme Court heard arguments in Sackett v. U.S. Environmental Protection Agency (EPA), a case that could decide the reach of the Clean Water Act (CWA). Many observers assumed that the court’s conservative justices would seize on the case to strike a blow against what they view as government overreach.

But at oral argument, some of those justices struggled to square simplistic industry arguments with science and common sense. As a former Supreme Court clerk and environmental lawyer, I’ve seen justices emerge from similar struggles with a more nuanced understanding of the realities of environmental regulation — and I have some hope that it might happen again here.

In the CWA, Congress broadly instructed the federal government to protect the “waters of the United States.” For decades, federal agencies in both Republican and Democratic administrations have interpreted that phrase to include wetlands that are closely intertwined with nearby surface waters.

The Supreme Court has addressed the issue itself, most recently in the 2006 case of Rapanos v. U.S. There, former Justice Anthony Kennedy wrote a controlling opinion that states that the CWA covers wetlands that have a “significant nexus” to surface waters. Lower courts and federal agencies built a stable regulatory framework on that opinion.

But industry groups remained frustrated. They would have preferred a far more restrictive approach championed by former Justice Antonin Scalia in a separate opinion that only attracted three other votes. Industry interests have been eager to relitigate Rapanos, hoping the newly constituted court will vote Justice Scalia’s minority opinion into law.

They found a cause célèbre in Michael and Chantell Sackett. Years ago, the couple purchased a small parcel of land near Idaho’s Priest Lake. The Army Corps of Engineers had told prior owners that the property contained wetlands covered by the CWA, but that they could develop the property if they got a permit.

As the owners of an excavation business, the Sacketts presumably knew they could get one. But they decided not to bother, and dumped 4,000 tons of gravel into their wetland instead. When a local resident complained to the EPA and the Corps, the agencies told the Sacketts that they had to undo the damage.

The Sacketts sued the EPA instead. They were represented by the Pacific Legal Foundation — a group that routinely attacks environmental protections — and were backed by dozens of polluting industries and conservative organizations that filed 28 amicus briefs in the court.

The Sacketts and their industry allies have asked the court to rule that the CWA only protects wetlands that are contiguous with and impossible to distinguish from adjacent waterways. Under their approach, a dike, a berm, a road or even a beaver dam could deprive a wetland of CWA protection. If summer heat seasonally dries out a patch of land between the wetland and the waterway — which is a common occurrence across the West — that too could end its legal protections.

The Sacketts’ sweeping argument exposes the broad ambitions of their backers. Their approach wouldn’t just eliminate protections for the wetlands on their Idaho lot — it would cut off protections for over 45 million acres of other wetlands too. If the court agrees with their legal position, oil and gas companies, mining companies and developers could pollute and fill those wetlands with impunity.

This is the most conservative court in modern history, and it is deeply skeptical of government regulation, as shown by opinions addressing things ranging from COVID-19 vaccination requirements to Clean Air Act regulations. And yet, at the Oct. 3 argument, many justices — including some conservatives — seemed reluctant to adopt the Sacketts’ position.

Justice Amy Coney Barrett recognized that the CWA expressly refers to wetlands, and that this poses “the biggest problem” for the Sacketts’ interpretation — which excludes basically all wetlands from the act. Chief Justice John Roberts questioned whether the Sacketts’ view that wetlands lose protection if they sometimes dry up seasonally was at odds with scientific reality, because this is “pretty common” for wetlands.

And Justice Brett Kavanaugh repeatedly observed that “seven straight administrations,” including the Trump administration, interpreted the CWA more broadly than the Sacketts. The reason for that consistency lies in a point Justice Ketanji Brown Jackson emphasized: Congress’ purpose in passing the CWA was clear — to ensure “the integrity of the nation’s waters” — and everyone agrees that wetlands filter pollutants, trap sediment, and store water to reduce flood risk.

The Sacketts’ effort to exclude nearly all wetlands from the CWA faces the problem that their narrow interpretation, as Justice Jackson put it, “does not relate in any way” to Congress’s protective objective.

Make no mistake: The justices — including several liberals — also fretted about the significant nexus test from Rapanos. They recognized that the test doesn’t lend itself to bright-line rules, and requires scientific judgment and site-specific inquiries. And they worried that landowners are not always able to determine immediately and for themselves whether they need permits before starting construction.

This tension reminded me of the court’s most recent CWA decision in County of Maui v. Hawaiʻi Wildlife Fund — a case that my employer, Earthjustice, litigated on behalf of local environmental groups. There, the court wrestled with a similar problem: whether the Clean Water Act’s prohibition on discharges to surface water applied to a sewage treatment plant that injected its effluent into a well very close to the ocean.

The Trump administration and industry allies argued that the court should exempt the plant, because it is not easy to draw a clean logical line between that treatment plant and, say, a leaky residential septic tank that trickles waste into the ocean. Many observers predicted that the court would throw the bathwater out with the baby in Maui County.

But it did not. Instead, Chief Justice Roberts and Justice Kavanaugh joined with the court’s then-four liberal members to hold that in determining what kinds of subsurface discharges the CWA covers, courts and agencies must consider each case and weigh many factors.

For instance: How far away is the discharge from surface water? How long does it take for the discharge to reach those waters? To those who sought a simpler, and narrower, test, the court apologized: “There are too many potentially relevant factors applicable to factually different cases for this Court now to use more specific language.”

It encouraged the EPA to issue regulations and guidance to clarify the matter — and it reminded the regulated community that the judiciary would be there to protect truly innocent parties from hefty fines or legal mousetraps.

After listening to the argument, I have some hope that we will see a similar result in Sackett. Having now grappled themselves with the scientific complexities and line-drawing challenges of how to decide what wetlands should be protected, Justice Roberts and Justice Kavanaugh — and perhaps others — might conclude again that the project of protecting water quality is not always amenable to bright-line legal tests.

As they did in Maui County, they might instead list a nonexclusive set of factors for courts and agencies to consider in determining whether a given wetland is covered by the CWA, and then repeat its commonsense reminder: “The object in a given scenario will be to advance, in a manner consistent with the statute’s language, the statutory purposes that Congress sought to achieve.”

That would be the right result, one that is faithful to the CWA and the ambitious goal Congress laid out: to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.”

Earthjustice filed an amicus brief in Sackett v. EPA on behalf of 17 Native tribes. Read more about Sackett v. EPA.