There was an agreement, but now one side is contesting it.
There was a federal waiver, but it's been revoked by the new administration.
There was a cease-and-desist letter from the Justice Department, which was essentially responded to with a middle finger and a lawsuit from the fourth-largest economy in the world.
Oh, and there's the ongoing tug-of-war between the fight for cleaner air and the industry responsible for moving approximately 70% of all goods in the United States.
Intrigued? Given the details of a slugfest with a likely future date in front of the U.S. Supreme Court, that's not surprising. Four manufacturers of semi trucks filed suit in federal court on August 11, 2025, claiming that the Clean Truck Partnership they entered into with California in 2023 is now unconstitutional. The suit was filed on the same day that the manufacturers agreed to a joint dismissal of a suit filed by the state of Nebraska over unfair pricing of diesel trucks.
Targeting the California Air Resources Board (CARB), the agency's Executive Officer, and Governor Gavin Newsom, the original equipment manufacturers (OEM) charge that the Trump administration's revocation of a waiver granted by the Biden administration makes California's continued enforcement of the Clean Truck Partnership unconstitutional. The defendants disagree, setting the stage for the courtroom version of Mad Max: Fury Road.
The Chaos Is a Feature, Not a Bug
The state of California has become one of the world's largest proponents of alternative energy sources, often leading by example. Since the Clean Air Act of 1970 was passed, California has received over 100 waivers to exceed federal regulations regarding environmental issues like pollution (the existence of EPA waivers is often contested and can depend on the presidential administration in power).
In 2023, CARB entered into an agreement with close to a dozen semi-truck manufacturers and associations that called for a move toward zero-emission vehicles (ZEVs) and the phasing out of diesel engines and other heavy pollutants over several years. Called the Clean Truck Partnership, it allowed for some flexibility for the OEMs with a goal of all-ZEV trucks by 2045.
In June 2025, Congress "disapproved" of California's emission standards and declared them void, which President Trump signed into law on June 12. In the meantime, a lawsuit filed in November 2024 by the state of Nebraska accused four semi-truck OEMs of antitrust violations by prioritizing ZEVs over vehicles with diesel engines, which caused the prices for the latter to rise. The suit noted that the manufacturers — Daimler Truck North America, International Motors, Paccar, and Volvo Group North America - were doing so in response to California's Clean Truck Partnership.
In the aftermath of the federal government's revocation of California's waiver, Nebraska and the OEMs evidently decided that the fight shouldn't be between them. On August 11, the same day that the OEMs filed suit against CARB, the Nebraska lawsuit reached a Joint Stipulation of Dismissal With Prejudice, with Nebraska Attorney Mike Hilgers claiming victory against the "destructive ideological agenda."
That's a Big Ten-Four, Good Buddy
In the lawsuit against CARB, the OEMs claim that California's continued enforcement of the Clean Truck Partnership has put them in an impossible position. They argue that California's legal battle with the federal government over the rollback means the OEMs can't plan out future production without knowing what guidelines and restrictions they'll be operating under, and that it's unfair for CARB and the state to continue to impose the agreement.
The suit seeks to give the Clean Air Act federal precedence over any emission laws passed by CARB and California and to enjoin both from attempting to impose or enact laws that violate federal law. It also demands that the Clean Truck Partnership be declared unconstitutional, releasing the OEMs and associations from the agreement.
Neither CARB nor California has given any indication of backing down. They probably don't have nice things to say about Nebraska's role in all this, either.
Related Resources
- What Does It Mean To Settle a Case? (FindLaw's Litigation and Appeals)
- What Is Antitrust Law and Trade Regulation? (FindLaw's Choosing the Right Lawyer)
- What Is Environmental Law? (FindLaw's Learn About the Law)
