California Attorney General (AG) Rob Bonta is leading a coalition of 22 Democratic states and the District of Columbia to defend the Environmental Protection Agency’s (EPA) rule that sets stringent greenhouse gas emissions standards for heavy-duty vehicles. The coalition filed a motion to intervene in the U.S. Court of Appeals for the D.C. Circuit, where the EPA’s rule is facing a legal challenge from Republican AGs.

The EPA’s “Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles–Phase 3” rule, finalized in March, allegedly reduces emissions from heavy-duty vehicles such as freight trucks and buses. The Democratic AGs argue that these standards are crucial for mitigating the adverse effects of climate change and criteria pollution in their states.

The coalition’s motion to intervene states that if the petitioners prevail, allegedly harmful emissions threatening public health and the environment will increase, exacerbating climate change and public health harms. The coalition claims that the increased emissions would be long-lasting due to the longevity of greenhouse gases in the atmosphere and the longevity of higher-emitting vehicles sold under weakened standards.

The legal challenge to the EPA’s rule comes from a group of 24 Republican AGs led by Nebraska AG Mike Hilgers, who allege that the rule exceeds the agency’s statutory authority. Simultaneously, a separate coalition of 17 states and the Nebraska Trucking Association filed a lawsuit in the U.S. District Court for the Eastern District of California, seeking to block California’s Advanced Clean Fleets regulation.

Why It Matters

The outcome of this legal battle will have significant implications for the nation’s transportation sector. The case also highlights the ongoing tension between state-led environmental initiatives and the federal government’s regulation of emissions standards.


Troutman Pepper State Attorneys General Team

Ashley Taylor – Co-leader and Firm Vice Chair
Ashley is co-leader of the firm’s nationally ranked State Attorneys General practice, vice chair of the firm, and a partner in its Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group. He helps his clients navigate the complexities involved with multistate attorneys general investigations and enforcement actions, federal agency actions, and accompanying litigation.
Clay Friedman – Co-leader
Clayton is a partner in the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group and co-leader of the State Attorneys General practice, multidisciplinary teams with decades of experience crafting effective strategies to help deter or mitigate the risk of enforcement actions and litigation.
Judy Jagdmann
Judy is a partner in the firm’s Regulatory Investigations, Strategy and Enforcement (RISE) practice, based in the Richmond office. She brings experience serving as chair and commissioner of the Virginia State Corporate Commission (VSCC) from 2006 through 2022, which includes regulating the utilities, insurance, banking, and securities industries. She also served as Virginia’s attorney general from 2005-2006.
Stephen Piepgrass
Stephen leads the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group. He focuses his practice on enforcement actions, investigations, and litigation. Stephen primarily represents clients engaging with, or being investigated by, state attorneys general and other state or local governmental enforcement bodies, including the CFPB and FTC, as well as clients involved with litigation, with a particular focus on heavily regulated industries.
Michael Yaghi
Michael is a partner in the firm’s State Attorneys General and Regulatory Investigations, Strategy + Enforcement (RISE) Practice Groups, nationwide teams that advise clients on consumer protection enforcement matters and other regulatory issues.
Samuel E. “Gene” Fishel
Gene is a member of the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) practice, based in the Richmond office. He brings extensive regulatory experience, having most recently served as senior assistant attorney general and chief of the Computer Crime Section in the Office of the Attorney General of Virginia, and as special assistant U.S. attorney in the Eastern District of Virginia for 20 years.
Tim Bado
Tim is an associate in the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group, where he represents corporations and individuals facing potential civil and criminal exposure. Tim’s experience in government investigations, enforcement actions, and white-collar litigation spans a number of industries, including financial services, pharmaceutical, health care, and government contracting, among others.
Chris Carlson
Chris Carlson represents clients in regulatory, civil and criminal investigations and litigation. In his practice, Chris regularly employs his prior regulatory experience to benefit clients who are interacting with and being investigated by state attorneys general.
Blake R. Christopher
Blake collaborates with clients on matters related to government contracting, investigations, and disputes. His senior-level government experience generates valuable insights and strategies for clients across a variety of industries.
Natalia Jacobo
Natalia is an associate in the firm’s Regulatory Investigations, Strategy and Enforcement (RISE) practice. She focuses her practice on two primary areas: government contracting and state attorney general work.
Namrata Kang
Namrata (Nam) is an associate in the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group, based in the Washington, D.C. office. She routinely advises clients on a wide variety of state and federal regulatory matters, with a particular emphasis on state consumer protection laws relating to consumer financial services and marketing and advertising.
Michael Lafleur
Michael is an associate in the firm’s Regulatory Investigations, Strategy, and Enforcement Practice Group. Based out of the firm’s Boston office, Mike has deep experience in litigation, investigations, and other regulatory matters involving state-level regulators and state attorneys general.
Susan Nikdel
Susan is an associate in the firm’s Consumer Financial Services Practice Group, and focuses her practice on consumer financial services matters. She has defended several of the nation’s largest and most influential financial institutions in individual and class action litigation involving the Telephone Consumer Protection Act (TCPA), Fair Credit Reporting Act (FCRA), Fair Debt Collection Practices Act (FDCPA), and other consumer privacy statutes.
John Sample
John is an associate in the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group. He focuses his practice on a wide range of general and complex litigation matters, including shareholder disputes, fraud, products liability, breach of contract, and Biometric Information Privacy Act claims.
Whitney Shephard
Whitney is an associate in the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group. She represents clients facing state and federal regulatory investigations and enforcement actions, as well as related civil litigation.
Trey Smith
Trey is an associate in the firm’s Regulatory Investigations, Strategy + Enforcement Practice. He focuses his practice on helping financial institutions and consumer facing companies navigate regulatory investigations and resulting litigation.
Daniel Waltz
Daniel is a member of the firm’s Regulatory Investigations, Strategy + Enforcement (RISE) Practice Group and State Attorneys General team. He counsels clients in connection with navigating complex government investigations, regulatory compliance, and transactions, involving state and federal government contracting obligations. Drawing on his broad experience as a former assistant attorney general for the state of Illinois, Daniel is a problem solver both inside and outside the courtroom.
Stephanie Kozol
Stephanie is Troutman Pepper’s senior government relations manager in the state attorneys general department.