Environmental groups are taking issue with President Trump’s executive order instructing the U.S. Environmental Protection Agency to consider interpreting the term “navigable waters” in a manner consistent with the late Justice Antonin Scalia’s opinion in Rapanos v. United States. In his opinion Justice Scalia concluded that the Clean Water Act only applies to relatively permanent surface waters and wetlands connected to larger bodies of water. To bolster his opinion, Scalia relied on the definition of “waters” contained in Webster’s New International Dictionary: Second Edition, which was published in 1931. Webster’s Second states that waters are “found in streams and bodies forming geographical features such as oceans, rivers [and] lakes.” However, some opponents of Scalia’s Rapanos decision have argued that because the Clean Water Act was written in 1972, Scalia should have instead looked to the definition of “waters” contained Webster’s Third New International Dictionary to truly discern what Congress intended when the Act was written. Webster’s Third, published in 1961, supposedly defines “waters” more broadly than the Second Edition, stating that waters are “the water occupying or flowing in a particular bed.”

President Donald Trump’s executive order calling for review of the Obama administration’s Clean Water Rule instructed the U.S. Environmental Protection Agency to consider interpreting the term “navigable waters” in a manner consistent with Scalia’s Rapanos decision. This represents a break from several circuit courts, who have relied on Justice Anthony Kennedy’s stand-alone opinion in the Rapanos case when interpreting the scope of the Clean Water Act.  In his opinion, Kennedy stated that wetlands and small waterways fall under federal jurisdiction if they have a “significant nexus” to an actual navigable waterway.  In contrast, the Obama Administration took the opposite approach from the Trump Administration, seeking to define “Navigable Waters” even more broadly than the Kennedy opinion.