State of Ohio v. EPA, 969 F.3d 306

In July 2015 Ohio and Tennessee sued to preliminarily enjoin the EPA and Army Corps’ 2015 "Clean Water Rule" interpreting "waters of the United States."
The Agencies suspended enforcement (2018), then repealed the 2015 Rule (Dec. 2019) and replaced it with the Navigable Waters Protection Rule (June 22, 2020).
The States moved for a preliminary injunction in 2018; the district court denied it in March 2019 for lack of imminent irreparable harm.
Separate litigation (about 15 district-court suits nationwide) challenges the Repeal and Protection Rules; some plaintiffs seek nationwide injunctions that could restore the 2015 Rule in other circuits.
The Sixth Circuit reviewed only an interlocutory appeal of the denial of the preliminary injunction and considered whether that appeal was moot given the repeal/replacement.
The court dismissed the interlocutory appeal as moot, vacated the district court’s denial under United States v. Munsingwear, Inc., and remanded for further proceedings.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Mootness of interlocutory appeal seeking preliminary injunction against the 2015 Rule	States: repeal/replacement does not eliminate risk because other courts could restore the 2015 Rule nationwide while this case is pending	Agencies: formal repeal and replacement remove any live controversy; preliminary relief would be pointless	Appeal is moot — a preliminary injunction would have no practical effect now; appeal dismissed
Effect of voluntary cessation by government on mootness	States: voluntary cessation by rulemaking is not dispositive; recurrence possible given multiple challenges elsewhere	Agencies: formal rulemaking provides solicitude and reduces likelihood of recurrence	Voluntary cessation does not automatically moot a case; here it moots the interlocutory appeal but not the underlying case
Mootness of case as a whole and vacatur of district order	States: case should remain live because there is a reasonable prospect the 2015 Rule could be restored nationwide	Agencies: repeal/replacement argues to the contrary	The case as a whole is not moot (reasonable possibility of recurrence exists); district court’s denial of preliminary injunction is vacated and the case remanded

Marbury v. Madison, 5 U.S. (1 Cranch) 137 (U.S. 1803) (Article III judicial power limits).
DeFunis v. Odegaard, 416 U.S. 312 (U.S. 1974) (mootness doctrine where decision would lack practical effect).
Friends of the Earth, Inc. v. Laidlaw Envtl. Servs., Inc., 528 U.S. 167 (U.S. 2000) (voluntary cessation and recurrence standard).
Los Angeles Cty. v. Davis, 440 U.S. 625 (U.S. 1979) (no reasonable expectation of recurrence test).
Univ. of Texas v. Camenisch, 451 U.S. 390 (U.S. 1981) (distinguishing preliminary and permanent injunction considerations).
United States v. Munsingwear, Inc., 340 U.S. 36 (U.S. 1950) (vacatur of lower-court orders when appeal becomes moot).
Speech First, Inc. v. Schlissel, 939 F.3d 756 (6th Cir. 2019) (degree of solicitude for formal governmental cessation).
D.T. v. Sumner Cty. Sch., 942 F.3d 324 (6th Cir. 2019) (interlocutory appeals of preliminary injunctions).
Nat'l Ass'n of Mfrs. v. Dep't of Defense, 138 S. Ct. 617 (U.S. 2018) (venue questions in challenges to the Rule).