The Supreme Court’s decision this morning in Sackett v. EPA continues a welcome trend of requiring that statutes have fixed definitions that do not allow for ambiguity at the outer margins — ambiguity that prosecutors and administrative agencies, such as the Environmental Protection Agency, exploit in order to concoct crimes that Congress has not codified and to extend regulatory reach to places and activities jurisdiction over which Congress never vested in bureaucrats.

I will have more to say in a few days about the Court’s clipping of prosecutorial wings a couple of weeks back in two cases involving cronies of former New York governor Andrew Cuomo, in which the justices threw out convictions because prosecutors extended the concept of fraud beyond recognition. The lesson was plain: Criminal statutes are supposed to put people of ordinary intelligence on notice of exactly what is forbidden. The predilections of progressives notwithstanding, it is intolerable for these laws to have vague borders, beyond their heartland applications, that enable “good governance” types to impose their vision of appropriate behavior — e.g., invoking fraud, which involves deceptive schemes to obtain money or tangible property, to manufacture such “crimes” as a fiduciary’s denial of honest services.

Importantly, the Court is not saying that such standards may not be imposed (as long as they don’t violate the Constitution). The justices are saying that, if such standards are to be imposed, they have to be enacted by Congress, and they have to satisfy the due process standard of definiteness — the average person has to be able to understand what has been banned.

Sackett continues this trend.

For years, the EPA has been using the vagueness of the Clean Water Act’s definition of navigable waters to extend its regulatory reach. The term navigable waters had a well-established meaning when the CWA was enacted in 1972; but Congress mucked things up by defining navigable waters as “the waters of the United States.” Over time, the EPA has stretched this term, such that it could mean the Mississippi River or a puddle in your backyard. Progressive environmental activists in the bureaucracy have used this ambiguity to stop people from building on their property, halt business development, etc. In the case at bar, for example, the Sacketts were prevented from building on their soggy Idaho property, with regulators and lower courts ruling that it constituted “wetlands” — enough to be “waters of the United States” — even though it was remote from any permanent body of water.

This definitional problem has festered because the Court failed to resolve it in the 2006 Rapanos case. Four conservative justices would have opted for a definitive standard that enabled the EPA to regulate traditional interstate navigable waters (e.g., rivers) and wetlands that were so physically close to those waters that they were practically indistinguishable. Four progressive, administrative-state-friendly justices would have deferred to the EPA’s assessment of the extent of its jurisdiction. As ever, Anthony Kennedy, the swing justice, prescribed an eccentric split-the-baby standard that no one could grasp and that has since led to endless litigation: The EPA could regulate if there was a “significant nexus” between wetlands and traditional navigable waters.

Today in Sackett, the Court renounced Justice Kennedy’s unworkable definition, with a majority prescribing the standard that the conservative plurality in Rapanos had argued for. That standard, in today’s majority opinion by Justice Samuel Alito (who was in that Rapanos plurality), states:

The CWA’s use of “waters” encompasses only those relatively permanent, standing or continuously flowing bodies of water forming geographical features that are described in ordinary parlance as “streams, oceans, rivers, and lakes.”

A couple of other points. The Court’s ruling today is nominally unanimous because all justices agreed that the Sacketts’ property rights were violated. But there remains the sharp divide between conservatives and progressives, as well as the mushy middle.

Justice Alito’s majority opinion was joined by Chief Justice John Roberts, along with Justices Clarence Thomas, Neil Gorsuch, and Amy Coney Barrett. Justice Thomas, joined by Justice Gorsuch, penned a concurring opinion emphasizing the history of the term “navigable waters,” and how progressive administrations and bureaucrats have sought to expand it, just as they have done with the commerce clause, to spread Washington’s regulatory tentacles at the expense of liberty and property rights.

The mushy middle is filled by Justice Brett Kavanaugh — perhaps not coincidentally, formerly a clerk of Justice Kennedy (as was Gorsuch). As highlighted by the New York Times, Justice Kavanaugh complains that by narrowing the CWA’s coverage, the Court “will leave some long-regulated adjacent wetlands no longer covered . . . with significant repercussions for water quality and flood control throughout the United States.” For the progressives, Justice Elena Kagan accuses the majority of departing from textualism in this case, as she claims it with respect to the Clean Air Act case in last year’s ruling, West Virginia v. EPA:

There, the majority’s non-textualism barred the E.P.A. from addressing climate change by curbing power plant emissions in the most effective way. Here, that method prevents the E.P.A. from keeping our country’s waters clean by regulating adjacent wetlands. The vice in both instances is the same: the Court’s appointment of itself as the national decision maker on environmental policy.

Both of these positions are wrongheaded.

Justice Kavanaugh (whose opinion was joined by the Court’s three progressives — Justices Sonia Sotomayor, Kagan, and Ketanji Brown Jackson) is asking the Court to do policy. The Court’s job, however (as originalist-leaning Kavanaugh himself regularly acknowledges in other cases, thankfully), is to interpret what the statute says, not to skew its construction in order to reach policy results the justices deem desirable.

As for Justice Kagan’s opinion (joined by the two other progressives), the majority does apply the text; the problem is that the text is ambiguous. Kagan wants the ambiguity resolved by the regulator. The majority wants it confined to what it was publicly understood to mean at the time the statute was enacted.

And this gets to the heart of the matter. Pace Kagan, the Court has not “appointed itself as the national decision-maker on environmental policy.” The Court is saying that policy must be made in the political process of legislation: Congress may have the policy it wants to have, but it has to be clear and definite, not leave it to the EPA to work out the EPA’s authority.