In 2004, Michael and Chantell Sackett purchased a vacant lot about 300 feet from Priest Lake, one of the largest lakes in Idaho. Eight years earlier, the U.S. Army Corps of Engineers had determined that the lot contains wetlands which qualify as “navigable waters” under the Clean Water Act (CWA), meaning certain construction activities on the property would require a CWA permit. In 2007, without obtaining such a permit, the Sacketts began filling their lot with dirt and gravel to prepare for construction, and the Environmental Protection Agency (EPA) issued an administrative compliance order requiring them to restore the property to its natural state. The Sacketts sued in federal court, arguing that the EPA lacked jurisdiction over their property.

The case eventually made it to the Supreme Court in 2012. The Court permitted the Sacketts’ challenge to the EPA’s order to go forward but left open the question of whether the wetlands qualified as “navigable waters.” After further litigation, the U.S. Court of Appeals for the Ninth Circuit ruled in favor of the EPA, holding that the CWA did cover the wetlands on the Sacketts’ property. The Ninth Circuit applied the test set forth by Justice Kennedy in his concurring opinion in Rapanos v. United States, concluding that the Sacketts’ property constituted “navigable waters” because of the existence of a “significant nexus between the wetlands in question and navigable waters in the traditional sense.” In 2022, the Supreme Court agreed to hear the case for a second time to clarify the proper test for determining whether wetlands are “navigable waters” under the CWA.

On June 17, 2022, CAC filed an amicus brief in support of the EPA, urging the court to affirm the ruling of the court below. Our brief refuted a distinct argument advanced by the Sacketts: that application of Justice Kennedy’s “significant nexus” test would extend the federal government’s CWA jurisdiction beyond the confines of Congress’s Commerce Clause power.

First, our brief explained that the Framers designed the Constitution to grant the federal government broad power to address issues of national concern. When the Framers gathered in Philadelphia to draft the Constitution, they had spent nearly a decade living under the failed Articles of Confederation, which created a central government so weak it was unable to coordinate responses to issues of national concern. The Founders adopted Article I of the Constitution with the understanding that Congress would have the power to regulate all matters that could not be solved by any state alone.

To that end, the Commerce Clause, which authorizes Congress to “regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes,” empowers Congress to pass laws regarding not just trade and other economic transactions, but a broader set of interrelated activities and affairs that require a coordinated, centralized response. Under the original meaning of the Commerce Clause, any issue that posed a collective action problem or spillover effects that could not be adequately addressed by a single state alone could be regulated by Congress. Water pollution, including through the filling of wetlands that provide important filtering and other ecological functions to protect larger bodies of water, is the prototypical example of such a problem.

Thus, our brief culminated by explaining that the text and history of the Commerce Clause make clear that regulations of wetlands with a “significant nexus” to traditional navigable waters fall squarely within Congress’s power. As we explained, the Supreme Court has repeatedly held that Congress has extensive authority over the waters of the United States as “channels of interstate commerce.” Justice Kennedy’s test itself, by instructing that the significant-nexus requirement is met only “if the wetlands, either alone or in combination with similarly situated lands in the region, significantly affect the chemical, physical, and biological integrity of other covered waters more readily understood as navigable,” necessarily ensures that the CWA only permits regulations of those wetlands that fit within Congress’s traditional channels-of-commerce authority. In other words, those wetlands that have no nexus—or a less than a “significant” one—to traditional navigable waters and thus might also have a more tenuous relationship to interstate commerce are excluded from the scope of federal regulation under Justice Kennedy’s construction of the CWA.

Furthermore, we explained that the significant nexus test also falls within Congress’s long-established power to regulate activities that substantially affect interstate commerce. Destruction of wetlands with a significant nexus to the channels of interstate commerce could impair the ability of those channels to support interstate commerce by rendering them unfishable, unable to support commercial recreation, or otherwise unfit for commercial activity. In this way, we argued, the federal government’s regulation of the pollution and filling of these wetlands is also justifiable as the regulation of an activity that substantially affects interstate commerce.

On May 25, 2023, the Supreme Court issued an opinion reversing the decision of the Ninth Circuit. Although all nine justices agreed that the Clean Water Act does not extend to the wetlands on the Sacketts’ property, a slim majority of five justices adopted an exceedingly narrow test for ascertaining whether wetlands constitute “navigable waters” under the CWA. Justice Kavanaugh and Justice Kagan both penned concurrences in the judgment, joined by Justice Sotomayor and Justice Jackson, which called out the majority’s contortion of the language of the CWA and reliance on policy-driven canons of statutory interpretation to rewrite the powerful environmental protection statute that Congress enacted. Justice Thomas also wrote a concurrence that took a troublingly narrow view of Congress’s power under the Commerce Clause, ignoring the text and history of that constitutional provision we detailed in our brief. This decision will have far-reaching and potentially devastating impacts for the environment, and it is also another example of the conservative supermajority on the Court abandoning statutory text when doing so furthers those justices’ policy preferences.