Barring or Narrowing the Citizen Suit in 2026: Constitutional Challenges, Diligent Prosecution, CCSF, and Mootness

This session examines the threshold defenses now available to end or narrow a citizen suit before reaching the merits. It begins with emerging constitutional and executive-branch challenges, including PLF’s Article II and private nondelegation arguments in West Virginia Rivers Coalition v. Amsted Graphite and Tennessee Riverkeeper v. City of Springfield, DOJ’s position in NAACP v. xAI Corp. that its right to intervene includes the right to dismiss, and EPA’s “compliance first” policy as a potential avenue for resolving disputes with the agency during the 60-day notice period.   The session then addresses Suncor, focusing on the diligent prosecution bar, claim-by-claim matching, and waiver risks. It next examines how CCSF has fared in the Ninth Circuit, including Judge Davila’s Sunnyvale rulings and Puget Soundkeeper v. Port of Tacoma, which have so far preserved the enforceability of receiving-water terms “in the interim.” Finally, the session considers Naples and how obtaining permit coverage after a suit is filed may moot a no-permit claim, including the evidentiary record a defendant must establish to support that defense.