Administrative Law & Regulatory Litigation
Federal government actions and regulations can drastically alter the playing field for businesses and disrupt entire industries. In today’s high-stakes regulatory environment, Arnold & Porter delivers strategic, comprehensive solutions to our clients’ most complex challenges. We guide clients through significant executive branch actions across federal agencies – handling everything from rulemaking and investigations to statutory interpretation – and successfully litigate the disputes that follow. Our team advises across the full spectrum of administrative law, helping clients shape the regulatory landscape by crafting strategic comments during rulemaking, challenging resulting regulations, defending enforcement actions, and navigating adjudications and compliance demands. Our team features former high-ranking officials from the White House, Department of Justice (DOJ), Environmental Protection Agency (EPA), Department of Health and Human Services (HHS), Department of Defense (DoD), Department of the Interior (DOI), Office of Management and Budget (OMB), Federal Trade Commission (FTC), Securities and Exchange Commission (SEC), Office of the Comptroller of the Currency (OCC), and Consumer Product Safety Commission (CPSC) as well as numerous former law clerks of the U.S. Supreme Court, D.C. Circuit, and other key courts for administrative law litigation.
Our cross-disciplinary approach combines renowned regulatory expertise and deep administrative law knowledge with insights into the rulemaking process. We engage early through strategic agency advocacy, and, when necessary, bring our proven litigation prowess to bear, securing victories at every stage of rulemaking and judicial review.
We have won groundbreaking challenges under the Administrative Procedure Act (APA) and have unmatched expertise on recurring APA issues like arbitrary-and-capricious review, post-Chevron statutory interpretation, cutting-edge questions raised by Jarkesy and Loper Bright, and notice-and-comment requirements.
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Unrivalled Government Experience: Our attorneys have held senior legal and policy positions across the federal government, bringing invaluable insider knowledge, strategic insight, and credibility that enhances our ability to navigate, influence, and challenge agency actions.
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Creative, Comprehensive Solutions: We advise clients on all phases of the regulatory process, from preparing for new executive orders, to commenting on proposed regulations, to litigation and enforcement actions. Our cross-practice team advocates and shapes policy at the agency level and, if necessary, challenges agency actions in court.
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Proven Track Record: Our team has secured major victories at all levels of the federal system, from emergency injunctions in federal districts courts to precedent-setting cases at the U.S. Supreme Court and D.C. Circuit.
Experience Highlights
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AstraZeneca in achieving a complete victory in the Third Circuit against the government in a dispute over the federal 340B Drug Pricing Program, the nation’s second-largest prescription drug program.
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Major chemical manufacturer in APA challenge to regulatory action by EPA on constitutional, statutory, and arbitrary-and-capricious grounds.
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Immigrant rights organizations in securing a landmark Supreme Court victory blocking the addition of a citizenship question to the 2020 Census on APA grounds.
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Pharmaceutical trade association (PhRMA) in successful APA challenge to halt implementation of federal regulations instituting “most favored nations” drug-pricing scheme for Medicare. Obtained temporary restraining order; regulation was later rescinded without ever going into effect.
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City of Baltimore in securing preliminary injunction and summary judgment against changes to the regulations governing the Title X family planning program. On appeal, won initial hearing en banc and affirmance of the district court's grant of summary judgment.
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Ford Motor Company in regulatory litigation in the D.C. Circuit.
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Biofuels producers in an appeal to D.C. Circuit defending an EPA rule regarding the ethanol content of motor vehicle fuel.
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Property developer in successful appeal to the D.C. Court of Appeals regarding an agency’s application of historic preservation law to a major redevelopment project.
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Truck Trailer Manufacturers Association in successfully challenging EPA and NHTSA greenhouse gas standards in the D.C. Circuit, and in securing a two-year suspension of CARB enforcement pending federal resolution.
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Andreessen Horowitz in comments on the U.S. Federal Trade Commission’s proposed rule relating to liability for generative AI providers that provide the means or instrumentalities used in impersonation scams.
Key Contacts
Related Services
Recognition
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Chambers USAAppellate Law – Nationwide (2025)
Litigation: General Commercial: (California, Colorado, Illinois, Texas, New York, Washington, D.C.) (2025)
Environment (Nationwide) (2025); Competition/Antitrust (USA) (2025)
Financial Services Regulation: Banking—Enforcement & Investigations (Nationwide) (2025); Government Relations: Federal (2025) -
The National Law Journal"Appellate Hot List" finalist (2024), recognized for the tenth year
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Law360“Appellate Practice Group of the Year” (2023)
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BTI Consulting GroupIntimidating Opponent in Litigation (2025)
Most Feared in Litigation (2024) -
The Legal 500 USAppellate: Courts of Appeals (2025)
Appellate: Supreme Courts (states and federal) (2024)
Government Relations (2025)
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National Institute for Lobbying & EthicsArnold & Porter lawyers are the second most to have been honored with NILE top lobbying awards since the program’s inception in 2021.
