Developers have cheered in recent years as the Supreme Court has tightened its standing rules. In a decision issued on Friday in National Association of Home Builders v. EPA, the Court of Appeals for the District of Columbia may have hoist the developers on their own petard.

After EPA and the Army Corps of Engineers issued a determination that two reaches of the Santa Cruz River constitute “traditional navigable waters” under the Clean Water Act, the National Association of Home Builders sued. The complaint appears to have attached declarations referring to individuals who own property along tributaries of the two reaches, and who asserted that they are have applied for permits under the CWA. None of this was enough for the Court, which made four important points...