Partner, Davis Polk & Wardwell LLP
Kannon is the head of our Supreme Court & Appellate practice. He has argued 39 cases before the U.S. Supreme Court and has argued more than 150 appeals in courts across the country, including every federal court of appeals and numerous state courts.
Kannon is ranked as a “Star Individual” in appellate law by Chambers USA, where a client notes, “It’s hard to think of enough superlatives to describe his talent, his judgment, his ability, his experience – he is as good as it gets.” Legal 500 U.S. recognizes Kannon in its Hall of Fame for appellate work. A client shares, “His work is the best in the business, and he is a wonderful human being in addition to being a world-class appellate litigator.”
In 2024 and 2022, Kannon was a finalist for the American Lawyer’s “Litigator of the Year” award. He was named “Appellate Litigator of the Year” by Benchmark Litigation in 2021 and was a 2026 finalist for that recognition.
Before entering private practice, Kannon served as an Assistant to the Solicitor General at the U.S. Department of Justice.
Managing Partner, Boyden Gray PLLC
Michael Buschbacher is the managing partner of Boyden Gray PLLC. He represents public and private companies, trade associations, non-profits, and individuals in high-stakes litigation and administrative proceedings, with a particular focus on environmental and energy matters.
In addition to trial-level work, Mr. Buschbacher maintains an active appellate practice, both as merits counsel and as counsel for amici curiae. He has written amicus briefs quoted by the Seventh and Ninth Circuits. And his Supreme Court advocacy has been cited by The New Yorker, The New York Times, and E&E News. Mr. Buschbacher’s commentary on legal issues has been published in The Wall Street Journal, Newsweek, and The American Conservative.
Before joining the firm, Mr. Buschbacher served at the U.S. Department of Justice as counsel to the Assistant Attorney General for the Environment and Natural Resources Division. There, he advised senior Department leadership, served as the lead attorney on several lawsuits, and helped draft policy memoranda for the Department on the proper scope and procedure for environmental enforcement. Prior to serving in the government, Mr. Buschbacher was an associate in the D.C. office of Sidley Austin.
Mr. Buschbacher is a former clerk to Judge Alice M. Batchelder of the U.S. Court of Appeals for the Sixth Circuit and to Magistrate Judge Paul R. Cherry of the U.S. District Court for the Northern District of Indiana.
Mr. Buschbacher holds a B.A. in Music and Germanic Studies from Indiana University and a J.D., magna cum laude, from Notre Dame Law School.
Attorney, Separation of Powers, Pacific Legal Foundation
Josh Robbins is an attorney in Pacific Legal Foundation’s separation of powers group. He litigates cases to defend the structural protections of the U.S. and state constitutions that guarantee liberty for all Americans. He wants to help ensure Americans receive due process from the government when their lives and property are at stake and that the laws are made by our democratically elected representatives and not by unaccountable bureaucrats.
As an attorney in private practice, Josh saw firsthand how the government can embroil people (and even large corporations) in years-long legal battles. At PLF, he works to provide those without great resources an opportunity to vindicate their right to a properly ordered government, which is the right of all Americans.
Prior to joining PLF, Josh was an associate at a large law firm where he litigated cases in federal and state courts. He clerked for the Honorable Jerry E. Smith of the United States Court of Appeals for the Fifth Circuit in Houston.
Josh earned a B.A. in economics and international studies from Yale University and a J.D. from the University of Virginia School of Law. While at UVA, he served as an articles editor for the Virginia Law Review. He lives in Alexandria, Virginia, and enjoys hiking, swimming, and attending Washington Nationals games.
Josh is a member of the bar only in the states of Virginia and D.C.
Lecturer in Law, University of Pennsylvania Carey Law School
Matthew Lee Wiener served until recently as the twice-presidentially appointed Acting Chair and Vice Chair of the Administrative Conference of the United States (ACUS), as well as a member of its Council and its Executive Director. (In 2016, President Obama nominated him to be ACUS’s Chairman.)
He is now a special counsel to ACUS, co-chair of its Council on Federal Administrative Adjudication, and a lecturer at the University of Pennsylvania Carey Law School, where he teaches Administrative Law.
Before affiliating with ACUS, Mr. Wiener was general counsel to U.S. Senator Arlen Specter (Senate Committee on the Judiciary), counsel to the U.S. House of Representatives Committee on the Judiciary, a partner at Dechert LLP, and special counsel to Cuneo Gilbert & LaDuca.
He has taught courses on administrative law, administrative practice, regulation remedies, statutory interpretation, and separation of powers at the law schools of the University of Pennsylvania, Rutgers University, and George Mason University.
Mr. Wiener is an elected member of the American Law Institute, a fellow of the American Bar Foundation, and co-chair of the Adjudication Committee of the American Bar Association’s Section of Administrative Law and Regulatory Practice.
Mr. Wiener holds a J.D. from Stanford Law School, where he was Articles Editor of the Stanford Law Review, and an A.B. from William and Mary.
Partner, Gibson Dunn & Crutcher LLP
Miguel A. Estrada is a partner in the Washington, D.C. office of Gibson, Dunn & Crutcher.
Mr. Estrada has represented clients before federal and state courts throughout the country in a broad range of matters. He has argued 24 cases before the United States Supreme Court, and briefed many others. He has also argued dozens of appeals in the lower federal courts.
Best Lawyers® recognized Mr. Estrada as a 2020 Lawyer of the Year in Intellectual Property Litigation and as a Lawyer of the Year in Appellate Practice. He has been recognized by Benchmark Litigation as a 2020 U.S. Appellate Litigation “Star”. In 2014, The American Lawyer named Mr. Estrada a “Litigator of the Year,” praising his “brains and tenacity” and noting he is the lawyer to call for “a tough, potentially unwinnable case.” From 2014-2021, Chambers & Partners has named him as one of a handful of attorneys that it ranked in the top tier among the nation’s leading appellate lawyers. Chambers & Partners noted that “clients are impressed by his intellect and ability, with one saying, ‘His papers are just blindingly clear in what they say and devastating in how they marshal the arguments.’” The Atlantic described his oral argument in a 2014 high-profile separation-of-powers case as “one of the most dazzling arguments the marble chamber has heard in many years.”
Mr. Estrada was selected by his peers for inclusion in the 2020 edition of The Best Lawyers in America® in the area of Appellate Law, in addition to previous recognition by the publication in the specialties of Bet-the-Company Litigation, Commercial Litigation and Criminal Defense: White Collar, Intellectual Property Litigation, and Regulatory Enforcement Litigation in the areas of SEC, Telecom, and Energy. In 2017, he was elected as a member of the American Law Institute. In 2021, Mr. Estrada was named among the Lawdragon 500 Leading Lawyers in America. In 2004, Legal Times named him one of the top 12 appellate litigators in the D.C. area, noting that “people who follow appellate practice in Washington have known for several years that Estrada . . . is one of the best around.” Also in 2004, Washingtonian Magazine named him one of the top constitutional law lawyers “who could become one of the legends of the Supreme Court bar.”
Mr. Estrada joined Gibson Dunn in 1997, after serving for five years as Assistant to the Solicitor General of the United States. He previously served as Assistant U.S. Attorney and Deputy Chief of the Appellate Section, U.S. Attorney’s Office, Southern District of New York. In those capacities, Mr. Estrada represented the government in numerous jury trials and in many appeals before the U.S. Court of Appeals for the Second Circuit. Before joining the U.S. Attorney’s Office, Mr. Estrada practiced corporate law in New York with Wachtell, Lipton, Rosen & Katz.
Mr. Estrada is a Trustee of the Supreme Court Historical Society. He was formerly a member of the Board of Visitors of Harvard Law School.
Mr. Estrada served as a law clerk to the Honorable Anthony M. Kennedy in the U.S. Supreme Court from 1988 to 1989 and to the Honorable Amalya L. Kearse in the U.S. Court of Appeals for the Second Circuit from 1986 to 1987. He received a J.D. degree magna cum laude in 1986 from Harvard Law School, where he was editor of the Harvard Law Review. Mr. Estrada graduated with an A.B. degree magna cum laude and Phi Beta Kappa in 1983 from Columbia College, New York. He is fluent in Spanish and proficient in French.
Representative Supreme Court matters include:
In 2011, the Supreme Court appointed Mr. Estrada to brief and argue two criminal cases –Dorsey v. United States and Hill v. United States – in which the Solicitor General declined to defend the judgments of the court of appeals. Mr. Estrada was appointed to argue the position that the Solicitor General had declined to defend.
Mr. Estrada was also part of the team that successfully presented then Governor Bush’s position to the Supreme Court in Bush v. Gore (2000). Other cases that Mr. Estrada handled in the Supreme Court include Granholm v. Heald (2005) (dormant Commerce Clause and Twenty-First Amendment), Vermont Agency of Natural Resources v. United States ex rel. Stevens (2000) (False Claims Act, Article III standing and Eleventh Amendment immunity), Old Chief v. United States (1997) (rules of evidence), United States v. Mezzanatto (1995) (evidence and plea bargaining), United States v. Robertson (1995) (constitutional limits on Congress’s Commerce Clause powers), Citizens Bank of Maryland v. Strumpf (1995) (bankruptcy law), and NOW, Inc. v. Scheidler (1994) (RICO).
Recent Court of Appeals matters include:
In addition, Mr. Estrada is lead appellate counsel to Vivendi S.A. in two securities-fraud appeals from jury verdicts that are currently pending in the Second Circuit, and to the National Association of Broadcasters in a challenge to certain procedures promulgated by the FCC in connection with the upcoming Spectrum Auction. Mr. Estrada also recently presented argument before the D.C. Circuit on behalf of the tobacco industry in a first amendment challenge to certain compelled disclosures that were imposed as part of the government’s long-running civil RICO case against the industry.
Other matters:
Former Acting Assistant Attorney General, United States Department of Justice; Partner, Winston & Strawn LLP
Jonathan “Jon” Brightbill is a trial and appellate lawyer in Winston’s Washington, D.C. office, and a partner in the firm’s Litigation and White Collar, Regulatory Defense, and Investigations Practices. He represents public and private companies, corporate officers, and other individuals across white collar, regulatory defense, and government and internal investigation matters and rulemaking challenges, as well as complex commercial disputes, citizen suits, and class actions. His commercial litigation experience encompasses business disputes, false advertising, consumer protection and fraud, FCA, and extensive class action defense work; antitrust and unfair competition matters; and intellectual property litigation, such as trademarks, patents, and trade secrets.
Jon served as the Nation’s lead environmental civil and criminal enforcement official and litigator, as Acting Assistant Attorney General for the Environment & Natural Resources Division (“ENRD”) of the U.S. Department of Justice (DOJ). Jon led ENRD’s 425 lawyers, overseeing 6,500 active matters and managing an annual budget of more than $150 million. Jon brings highly experienced executive leadership from among the most senior level of DOJ on white collar and regulatory enforcement, as well as on federal policymaking and rulemaking development and challenges. He speaks with authority on government decision-making processes, and the arguments and perspectives that move regulators and enforcers, best advising and positioning clients to deal with challenges.
Jon argued many of the government’s most significant cases during his time with the DOJ. This included the Navigable Waters Protection Rule and Clean Water Rule Repeal (10th Cir., district courts), the Affordable Clean Energy Rule and Clean Power Plan Repeal (D.C. Cir), defense of EPA actions on pesticide tolerances under FIFRA and the FDCA (9th Cir. en banc), among numerous others. Jon represented the United States in trial courts in both enforcement and defensive cases, including federal enforcement action against Jeffrey Lowe and the Tiger King Park, of Netflix fame, securing a first-of-its-kind injunction for violations of the Endangered Species Act and Animal Welfare Act. Jon directed the litigation and briefing of scores of additional federal cases nationwide, covering all of the major environmental and natural resources statutes, such as the Clean Air Act, the Clean Water Act, FIFRA (pesticides), FDCA (food safety), TSCA (toxics), CERCLA (land remediation), RCRA (waste), National Environmental Policy Act, Federal Land Policy and Management Act, and numerous other land- and resource-management statutes.
Jon has unmatched experience litigating legal and technical issues relating to climate change. He argued in the courts of appeals, including the D.C. Circuit, regarding the most significant climate change regulations by EPA, as well as the preemptive scope of the Clean Air Act. Jon also litigated climate change-related credit and trading schemes and international agreements in district court. During Jon’s time in leadership at ENRD, it successfully defeated one of the most wide-ranging lawsuits regarding climate change to date—obtaining a stay pending interlocutory appeal and dismissal just weeks before a scheduled three-month trial on federal government liability for climate change.
An accomplished trial lawyer, prior to working at DOJ, Jon was a partner in the Washington, D.C. office of another global law firm. He not only represents clients in court, but creatively counsels corporations on balancing business needs and realities with a broad range of litigation risks and compliance obligations. Jon is also an Adjunct Professor at Georgetown University Law Center. He served on the American Bar Association’s E-Discovery Working Group for Bankruptcy Practice, and was a frequent lecturer for District of Columbia Bar Association Continuing Legal Education Programs.
Jon served as an appellate clerk for the Honorable D. Brooks Smith, U.S. Court of Appeals for the Third Circuit, after graduating magna cum laude from the Georgetown University Law Center. He worked in state government as an Executive Policy Specialist for air, waste, land remediation, and radiation matters at the Pennsylvania Department of Environmental Protection.
Laurence A. Tisch Professor of Law and Director, Classical Liberal Institute, New York University School of Law; Director, Classical Liberal Institute, Civitas Institute University of Texas at Austin
Richard A. Epstein is the Laurence A. Tisch Professor of Law, at New York University, a senior research fellow at the Civitas Institute at the University of Texas Austin, and a senior Lecturer, the University of Chicago. He received an LL.D., h.c . from the University of Ghent, 2003 , and an LLD h.c . from the University of Siegen in 2018 and the Bradley Prize in 2011. He has been a member of the American Academy of Arts and Sciences since 1985. He has edited both the Journal of Legal Studies (1981-1991) and the Journal of Law and Economics (1991-2001). He is also a founder and director of the Classical Liberal Institute at NYU Law School. His most recent book is The Classical Liberal Constitution: The Uncertain Quest for Limited Government (2014). His other books include Takings: Private Property and the Power of Eminent Domain ( 1985); Bargaining with the State (1993); Simple Rules for a Complex World (1995); Principles for a Free Society: Reconciling Individual Liberty and the Common Good (1998); Skepticism and Freedom: A Modern Theory of Classical Liberalism (2003); Design for Liberty: Private Property, Public Administration and the Rule of Law (2011), and most recently, The Myth of Birthright citizenship—and Beyond (2026). He has taught courses in , administrative law, antitrust, constitutional, contracts, environmental law, land use planning; real property, torts and water law. He has written and spoken extensively on a wide range of topics, and is writes a regular column for Defining Ideas.
Emmett Visiting Assistant Clinical Professor of Law in Environmental Law, Harvard Law School
Andrew Mergen is a Visiting Assistant Clinical Professor of Law and Faculty Director of the Emmett Environmental Law & Policy Clinic. Prior to joining the Harvard Law School faculty, Andrew Mergen served in the Appellate Section of the Environment & Natural Resources Division (ENRD) at the United States Department of Justice. Professor Mergen began his career at the Justice Department in the Honors Program and concluded his career as Chief of ENRD’s Appellate Section. He has presented oral arguments in all 13 federal courts of appeals, including two en banc courts, and before several state intermediate and supreme courts. He has also worked on over a dozen merits cases in the Supreme Court of the United States. In addition, in 2009, Professor Mergen assisted the Office of White House Counsel on the confirmation of the Honorable Sonia Sotomayor as Associate Justice of the Supreme Court. During his career at the Justice Department, Professor Mergen received the Attorney General’s Award for Distinguished Service three times. He also received ENRD’s Muskee-Chafee Award, honoring his work’s significant contribution to protecting the environment.
Before entering clinical teaching, Professor Mergen taught at several law schools including, Harvard Law School (Advanced Environmental Law), the University of Michigan Law School (Natural Resources Law) and the William S. Richardson School of Law, University of Hawaii-Manoa (Administrative Law). Professor Mergen has written about federal water rights in “A Misplaced Sensitivity: The Draft Opinions in Wyoming v. United States” (68 Colo. L. Rev. 683 (1997), with Sylvia F. Liu); energy development on public lands in “Surface Tension: The Problem of Federal Private Split Estates” (33 Land & Water L. Rev. 419 (1998)); climate change and the Endangered Species Act in “The Role of Climate Change in ESA Listing Decisions” (53 Rocky Mt. Min. L. Fdn. 67 (2016), with Murray Feldman) and the accommodation of Native American sacred sites on federal land in “Finding the Path Forward for Indigenous Sacred and Cultural Spaces on Federal Public Land,” 68 Nat. Resources & Energy L. Inst. 32-1 (2022). Professor Mergen is a graduate of the University of Wisconsin—Madison and the George Washington University Law School.
Robert F. Stanton Professor of Law, University of Maryland Carey School of Law
Robert V. Percival is the Robert F. Stanton Professor of Law and the Director of the Environmental Law Program at the University of Maryland School of Law. He received a B.A. summa cum laude from Macalester College, a J.D. from Stanford Law School and an M.A. in economics from Stanford University. At Stanford Percival was named the Nathan Abbott Scholar for graduating first in his law school class. Following graduation, he served as a law clerk for Judge Shirley M. Hufstedler of the U.S. Court of Appeals for the Ninth Circuit and for U.S. Supreme Court Justice Byron R. White. He joined the Maryland faculty in 1987 after serving as a senior attorney for the Environmental Defense Fund. Percival has served as a visiting professor of law at Harvard Law School, Georgetown University Law Center, the China University of Political Science and Law (Beijing), and Comenius University (Bratislava). He is the principal author of a leading environmental law casebook, now in its 9th edition, and the author of several articles about the Supreme Court and presidential authority over executive agencies. Percival wrote one of the first articles on the propriety of consent decrees to effectuate and enforce federal law “The Bounds of Consent: Consent Decrees, Settlements and Federal Environmental Policymaking,” 1987 Univ. Chic. Leg. F. 327 (1987). He also is the author of the first comprehensive analyses of what the papers of the late Justices Thurgood Marshall and Harry Blackmun reveal about the Supreme Court’s handling of environmental cases (“Environmental Law in the Supreme Court: Highlights from the Blackmun Papers,” 35 ELR 10637 (2005), and “Environmental Law in the Supreme Court: Highlights from the Marshall Papers,” 13 ELR 10606 (Oct. 1993)).
Vice President of Domestic and Economic Policy, The Heritage Foundation
Roger Severino is Vice President of Economic and Domestic Policy, and the Joseph C. and Elizabeth A. Anderlik Fellow at The Heritage Foundation.
Severino is a national authority on civil rights, conscience and religious freedom, the administrative state, and information privacy, particularly as applied to health care law and policy. Find his tweets at @RogerSeverino_.
Severino spearheaded the HHS Accountability Project while a Senior Fellow at EPPC from 2021 to 2023. Previously, Severino was Director of HHS’ Office for Civil Rights, where he led a team of over 250 staff enforcing our nation’s civil rights, conscience and religious freedom, and health information privacy laws. He served from 2017 to 2021 and was the longest-serving OCR director of the past three decades.
Prior to joining HHS, Severino served for two years as Director of the DeVos Center for Religion and Civil Society at Heritage, advocating for life, family, and religious-freedom policies. Before that, he was a trial attorney for seven years at the U.S. Department of Justice’s Civil Rights Division where he enforced the Fair Housing Act and the Civil Rights Act of 1964. Severino started his legal career at the Becket Fund for Religious Liberty, where he was Legal Counsel and Chief Operations Officer and defended the rights of people of all faiths under federal and international law.
Severino has been profiled in The New York Times, The Atlantic, The Wall Street Journal, and The Hill and has appeared on Fox News, CNN, MSNBC, NPR, and PBS, among others. In 2020, The New York Times dubbed him and his wife Carrie, “a conservative power couple” to be reckoned with.
Severino holds a JD from Harvard Law School, a master’s degree in public policy, with highest distinction, from Carnegie Mellon University, and a bachelor’s degree in business from the University of Southern California. He was appointed by President Trump to the Administrative Conference of the United States and is a member of the District of Columbia and the Commonwealth of Virginia bars.
As OCR director, Severino founded the federal government’s first division dedicated exclusively to conscience and religious freedom compliance and enforcement. He enforced the Weldon Amendment for the first time against a state (California) after it coerced families and religious organizations into paying for abortion insurance coverage, leading to a $200 million federal funding disallowance. He also enforced laws protecting pro-life pregnancy resource centers from discrimination by states hostile to their message and enforced laws prohibiting forced participation in abortions by medical professionals.
With respect to civil rights, Severino protected older persons and people with disabilities from being denied life-saving care due to discriminatory “quality of life” judgments, especially during the COVID-19 pandemic. He also achieved a landmark sexual harassment resolution with Michigan State University in the wake of the Larry Nassar sexual assault scandal and protected the rights of non-English speakers to have equal access to health and human services.
In the area of health privacy, he secured the largest HIPAA monetary settlement in history and achieved the largest number of enforcement resolutions both in a single year and across four years. He also facilitated the transformational use of Skype, Zoom, and Facetime for delivery of telehealth during the COVID-19 pandemic and beyond.
His regulatory reform activities resulted in a comprehensive conscience protection regulation and proposed a life-affirming disability rights regulation. He achieved regulatory savings of $3.6 billion in health care industry costs over five years and identified and proposed an additional $3.2 billion in cost savings from the repeal of ineffective and unnecessary regulatory burdens.
Severino is a Spanish speaker who teaches salsa and west coast swing in his spare time.
Managing Partner, Boyden Gray PLLC
Michael Buschbacher is the managing partner of Boyden Gray PLLC. He represents public and private companies, trade associations, non-profits, and individuals in high-stakes litigation and administrative proceedings, with a particular focus on environmental and energy matters.
In addition to trial-level work, Mr. Buschbacher maintains an active appellate practice, both as merits counsel and as counsel for amici curiae. He has written amicus briefs quoted by the Seventh and Ninth Circuits. And his Supreme Court advocacy has been cited by The New Yorker, The New York Times, and E&E News. Mr. Buschbacher’s commentary on legal issues has been published in The Wall Street Journal, Newsweek, and The American Conservative.
Before joining the firm, Mr. Buschbacher served at the U.S. Department of Justice as counsel to the Assistant Attorney General for the Environment and Natural Resources Division. There, he advised senior Department leadership, served as the lead attorney on several lawsuits, and helped draft policy memoranda for the Department on the proper scope and procedure for environmental enforcement. Prior to serving in the government, Mr. Buschbacher was an associate in the D.C. office of Sidley Austin.
Mr. Buschbacher is a former clerk to Judge Alice M. Batchelder of the U.S. Court of Appeals for the Sixth Circuit and to Magistrate Judge Paul R. Cherry of the U.S. District Court for the Northern District of Indiana.
Mr. Buschbacher holds a B.A. in Music and Germanic Studies from Indiana University and a J.D., magna cum laude, from Notre Dame Law School.
Attorney, Separation of Powers, Pacific Legal Foundation
Josh Robbins is an attorney in Pacific Legal Foundation’s separation of powers group. He litigates cases to defend the structural protections of the U.S. and state constitutions that guarantee liberty for all Americans. He wants to help ensure Americans receive due process from the government when their lives and property are at stake and that the laws are made by our democratically elected representatives and not by unaccountable bureaucrats.
As an attorney in private practice, Josh saw firsthand how the government can embroil people (and even large corporations) in years-long legal battles. At PLF, he works to provide those without great resources an opportunity to vindicate their right to a properly ordered government, which is the right of all Americans.
Prior to joining PLF, Josh was an associate at a large law firm where he litigated cases in federal and state courts. He clerked for the Honorable Jerry E. Smith of the United States Court of Appeals for the Fifth Circuit in Houston.
Josh earned a B.A. in economics and international studies from Yale University and a J.D. from the University of Virginia School of Law. While at UVA, he served as an articles editor for the Virginia Law Review. He lives in Alexandria, Virginia, and enjoys hiking, swimming, and attending Washington Nationals games.
Josh is a member of the bar only in the states of Virginia and D.C.
Lecturer in Law, University of Pennsylvania Carey Law School
Matthew Lee Wiener served until recently as the twice-presidentially appointed Acting Chair and Vice Chair of the Administrative Conference of the United States (ACUS), as well as a member of its Council and its Executive Director. (In 2016, President Obama nominated him to be ACUS’s Chairman.)
He is now a special counsel to ACUS, co-chair of its Council on Federal Administrative Adjudication, and a lecturer at the University of Pennsylvania Carey Law School, where he teaches Administrative Law.
Before affiliating with ACUS, Mr. Wiener was general counsel to U.S. Senator Arlen Specter (Senate Committee on the Judiciary), counsel to the U.S. House of Representatives Committee on the Judiciary, a partner at Dechert LLP, and special counsel to Cuneo Gilbert & LaDuca.
He has taught courses on administrative law, administrative practice, regulation remedies, statutory interpretation, and separation of powers at the law schools of the University of Pennsylvania, Rutgers University, and George Mason University.
Mr. Wiener is an elected member of the American Law Institute, a fellow of the American Bar Foundation, and co-chair of the Adjudication Committee of the American Bar Association’s Section of Administrative Law and Regulatory Practice.
Mr. Wiener holds a J.D. from Stanford Law School, where he was Articles Editor of the Stanford Law Review, and an A.B. from William and Mary.
Managing Partner, Boyden Gray PLLC
Michael Buschbacher is the managing partner of Boyden Gray PLLC. He represents public and private companies, trade associations, non-profits, and individuals in high-stakes litigation and administrative proceedings, with a particular focus on environmental and energy matters.
In addition to trial-level work, Mr. Buschbacher maintains an active appellate practice, both as merits counsel and as counsel for amici curiae. He has written amicus briefs quoted by the Seventh and Ninth Circuits. And his Supreme Court advocacy has been cited by The New Yorker, The New York Times, and E&E News. Mr. Buschbacher’s commentary on legal issues has been published in The Wall Street Journal, Newsweek, and The American Conservative.
Before joining the firm, Mr. Buschbacher served at the U.S. Department of Justice as counsel to the Assistant Attorney General for the Environment and Natural Resources Division. There, he advised senior Department leadership, served as the lead attorney on several lawsuits, and helped draft policy memoranda for the Department on the proper scope and procedure for environmental enforcement. Prior to serving in the government, Mr. Buschbacher was an associate in the D.C. office of Sidley Austin.
Mr. Buschbacher is a former clerk to Judge Alice M. Batchelder of the U.S. Court of Appeals for the Sixth Circuit and to Magistrate Judge Paul R. Cherry of the U.S. District Court for the Northern District of Indiana.
Mr. Buschbacher holds a B.A. in Music and Germanic Studies from Indiana University and a J.D., magna cum laude, from Notre Dame Law School.
Attorney, Separation of Powers, Pacific Legal Foundation
Josh Robbins is an attorney in Pacific Legal Foundation’s separation of powers group. He litigates cases to defend the structural protections of the U.S. and state constitutions that guarantee liberty for all Americans. He wants to help ensure Americans receive due process from the government when their lives and property are at stake and that the laws are made by our democratically elected representatives and not by unaccountable bureaucrats.
As an attorney in private practice, Josh saw firsthand how the government can embroil people (and even large corporations) in years-long legal battles. At PLF, he works to provide those without great resources an opportunity to vindicate their right to a properly ordered government, which is the right of all Americans.
Prior to joining PLF, Josh was an associate at a large law firm where he litigated cases in federal and state courts. He clerked for the Honorable Jerry E. Smith of the United States Court of Appeals for the Fifth Circuit in Houston.
Josh earned a B.A. in economics and international studies from Yale University and a J.D. from the University of Virginia School of Law. While at UVA, he served as an articles editor for the Virginia Law Review. He lives in Alexandria, Virginia, and enjoys hiking, swimming, and attending Washington Nationals games.
Josh is a member of the bar only in the states of Virginia and D.C.
Lecturer in Law, University of Pennsylvania Carey Law School
Matthew Lee Wiener served until recently as the twice-presidentially appointed Acting Chair and Vice Chair of the Administrative Conference of the United States (ACUS), as well as a member of its Council and its Executive Director. (In 2016, President Obama nominated him to be ACUS’s Chairman.)
He is now a special counsel to ACUS, co-chair of its Council on Federal Administrative Adjudication, and a lecturer at the University of Pennsylvania Carey Law School, where he teaches Administrative Law.
Before affiliating with ACUS, Mr. Wiener was general counsel to U.S. Senator Arlen Specter (Senate Committee on the Judiciary), counsel to the U.S. House of Representatives Committee on the Judiciary, a partner at Dechert LLP, and special counsel to Cuneo Gilbert & LaDuca.
He has taught courses on administrative law, administrative practice, regulation remedies, statutory interpretation, and separation of powers at the law schools of the University of Pennsylvania, Rutgers University, and George Mason University.
Mr. Wiener is an elected member of the American Law Institute, a fellow of the American Bar Foundation, and co-chair of the Adjudication Committee of the American Bar Association’s Section of Administrative Law and Regulatory Practice.
Mr. Wiener holds a J.D. from Stanford Law School, where he was Articles Editor of the Stanford Law Review, and an A.B. from William and Mary.
Former Acting Assistant Attorney General, United States Department of Justice; Partner, Winston & Strawn LLP
Jonathan “Jon” Brightbill is a trial and appellate lawyer in Winston’s Washington, D.C. office, and a partner in the firm’s Litigation and White Collar, Regulatory Defense, and Investigations Practices. He represents public and private companies, corporate officers, and other individuals across white collar, regulatory defense, and government and internal investigation matters and rulemaking challenges, as well as complex commercial disputes, citizen suits, and class actions. His commercial litigation experience encompasses business disputes, false advertising, consumer protection and fraud, FCA, and extensive class action defense work; antitrust and unfair competition matters; and intellectual property litigation, such as trademarks, patents, and trade secrets.
Jon served as the Nation’s lead environmental civil and criminal enforcement official and litigator, as Acting Assistant Attorney General for the Environment & Natural Resources Division (“ENRD”) of the U.S. Department of Justice (DOJ). Jon led ENRD’s 425 lawyers, overseeing 6,500 active matters and managing an annual budget of more than $150 million. Jon brings highly experienced executive leadership from among the most senior level of DOJ on white collar and regulatory enforcement, as well as on federal policymaking and rulemaking development and challenges. He speaks with authority on government decision-making processes, and the arguments and perspectives that move regulators and enforcers, best advising and positioning clients to deal with challenges.
Jon argued many of the government’s most significant cases during his time with the DOJ. This included the Navigable Waters Protection Rule and Clean Water Rule Repeal (10th Cir., district courts), the Affordable Clean Energy Rule and Clean Power Plan Repeal (D.C. Cir), defense of EPA actions on pesticide tolerances under FIFRA and the FDCA (9th Cir. en banc), among numerous others. Jon represented the United States in trial courts in both enforcement and defensive cases, including federal enforcement action against Jeffrey Lowe and the Tiger King Park, of Netflix fame, securing a first-of-its-kind injunction for violations of the Endangered Species Act and Animal Welfare Act. Jon directed the litigation and briefing of scores of additional federal cases nationwide, covering all of the major environmental and natural resources statutes, such as the Clean Air Act, the Clean Water Act, FIFRA (pesticides), FDCA (food safety), TSCA (toxics), CERCLA (land remediation), RCRA (waste), National Environmental Policy Act, Federal Land Policy and Management Act, and numerous other land- and resource-management statutes.
Jon has unmatched experience litigating legal and technical issues relating to climate change. He argued in the courts of appeals, including the D.C. Circuit, regarding the most significant climate change regulations by EPA, as well as the preemptive scope of the Clean Air Act. Jon also litigated climate change-related credit and trading schemes and international agreements in district court. During Jon’s time in leadership at ENRD, it successfully defeated one of the most wide-ranging lawsuits regarding climate change to date—obtaining a stay pending interlocutory appeal and dismissal just weeks before a scheduled three-month trial on federal government liability for climate change.
An accomplished trial lawyer, prior to working at DOJ, Jon was a partner in the Washington, D.C. office of another global law firm. He not only represents clients in court, but creatively counsels corporations on balancing business needs and realities with a broad range of litigation risks and compliance obligations. Jon is also an Adjunct Professor at Georgetown University Law Center. He served on the American Bar Association’s E-Discovery Working Group for Bankruptcy Practice, and was a frequent lecturer for District of Columbia Bar Association Continuing Legal Education Programs.
Jon served as an appellate clerk for the Honorable D. Brooks Smith, U.S. Court of Appeals for the Third Circuit, after graduating magna cum laude from the Georgetown University Law Center. He worked in state government as an Executive Policy Specialist for air, waste, land remediation, and radiation matters at the Pennsylvania Department of Environmental Protection.
Laurence A. Tisch Professor of Law and Director, Classical Liberal Institute, New York University School of Law; Director, Classical Liberal Institute, Civitas Institute University of Texas at Austin
Richard A. Epstein is the Laurence A. Tisch Professor of Law, at New York University, a senior research fellow at the Civitas Institute at the University of Texas Austin, and a senior Lecturer, the University of Chicago. He received an LL.D., h.c . from the University of Ghent, 2003 , and an LLD h.c . from the University of Siegen in 2018 and the Bradley Prize in 2011. He has been a member of the American Academy of Arts and Sciences since 1985. He has edited both the Journal of Legal Studies (1981-1991) and the Journal of Law and Economics (1991-2001). He is also a founder and director of the Classical Liberal Institute at NYU Law School. His most recent book is The Classical Liberal Constitution: The Uncertain Quest for Limited Government (2014). His other books include Takings: Private Property and the Power of Eminent Domain ( 1985); Bargaining with the State (1993); Simple Rules for a Complex World (1995); Principles for a Free Society: Reconciling Individual Liberty and the Common Good (1998); Skepticism and Freedom: A Modern Theory of Classical Liberalism (2003); Design for Liberty: Private Property, Public Administration and the Rule of Law (2011), and most recently, The Myth of Birthright citizenship—and Beyond (2026). He has taught courses in , administrative law, antitrust, constitutional, contracts, environmental law, land use planning; real property, torts and water law. He has written and spoken extensively on a wide range of topics, and is writes a regular column for Defining Ideas.
Emmett Visiting Assistant Clinical Professor of Law in Environmental Law, Harvard Law School
Andrew Mergen is a Visiting Assistant Clinical Professor of Law and Faculty Director of the Emmett Environmental Law & Policy Clinic. Prior to joining the Harvard Law School faculty, Andrew Mergen served in the Appellate Section of the Environment & Natural Resources Division (ENRD) at the United States Department of Justice. Professor Mergen began his career at the Justice Department in the Honors Program and concluded his career as Chief of ENRD’s Appellate Section. He has presented oral arguments in all 13 federal courts of appeals, including two en banc courts, and before several state intermediate and supreme courts. He has also worked on over a dozen merits cases in the Supreme Court of the United States. In addition, in 2009, Professor Mergen assisted the Office of White House Counsel on the confirmation of the Honorable Sonia Sotomayor as Associate Justice of the Supreme Court. During his career at the Justice Department, Professor Mergen received the Attorney General’s Award for Distinguished Service three times. He also received ENRD’s Muskee-Chafee Award, honoring his work’s significant contribution to protecting the environment.
Before entering clinical teaching, Professor Mergen taught at several law schools including, Harvard Law School (Advanced Environmental Law), the University of Michigan Law School (Natural Resources Law) and the William S. Richardson School of Law, University of Hawaii-Manoa (Administrative Law). Professor Mergen has written about federal water rights in “A Misplaced Sensitivity: The Draft Opinions in Wyoming v. United States” (68 Colo. L. Rev. 683 (1997), with Sylvia F. Liu); energy development on public lands in “Surface Tension: The Problem of Federal Private Split Estates” (33 Land & Water L. Rev. 419 (1998)); climate change and the Endangered Species Act in “The Role of Climate Change in ESA Listing Decisions” (53 Rocky Mt. Min. L. Fdn. 67 (2016), with Murray Feldman) and the accommodation of Native American sacred sites on federal land in “Finding the Path Forward for Indigenous Sacred and Cultural Spaces on Federal Public Land,” 68 Nat. Resources & Energy L. Inst. 32-1 (2022). Professor Mergen is a graduate of the University of Wisconsin—Madison and the George Washington University Law School.
Robert F. Stanton Professor of Law, University of Maryland Carey School of Law
Robert V. Percival is the Robert F. Stanton Professor of Law and the Director of the Environmental Law Program at the University of Maryland School of Law. He received a B.A. summa cum laude from Macalester College, a J.D. from Stanford Law School and an M.A. in economics from Stanford University. At Stanford Percival was named the Nathan Abbott Scholar for graduating first in his law school class. Following graduation, he served as a law clerk for Judge Shirley M. Hufstedler of the U.S. Court of Appeals for the Ninth Circuit and for U.S. Supreme Court Justice Byron R. White. He joined the Maryland faculty in 1987 after serving as a senior attorney for the Environmental Defense Fund. Percival has served as a visiting professor of law at Harvard Law School, Georgetown University Law Center, the China University of Political Science and Law (Beijing), and Comenius University (Bratislava). He is the principal author of a leading environmental law casebook, now in its 9th edition, and the author of several articles about the Supreme Court and presidential authority over executive agencies. Percival wrote one of the first articles on the propriety of consent decrees to effectuate and enforce federal law “The Bounds of Consent: Consent Decrees, Settlements and Federal Environmental Policymaking,” 1987 Univ. Chic. Leg. F. 327 (1987). He also is the author of the first comprehensive analyses of what the papers of the late Justices Thurgood Marshall and Harry Blackmun reveal about the Supreme Court’s handling of environmental cases (“Environmental Law in the Supreme Court: Highlights from the Blackmun Papers,” 35 ELR 10637 (2005), and “Environmental Law in the Supreme Court: Highlights from the Marshall Papers,” 13 ELR 10606 (Oct. 1993)).
Former Acting Assistant Attorney General, United States Department of Justice; Partner, Winston & Strawn LLP
Jonathan “Jon” Brightbill is a trial and appellate lawyer in Winston’s Washington, D.C. office, and a partner in the firm’s Litigation and White Collar, Regulatory Defense, and Investigations Practices. He represents public and private companies, corporate officers, and other individuals across white collar, regulatory defense, and government and internal investigation matters and rulemaking challenges, as well as complex commercial disputes, citizen suits, and class actions. His commercial litigation experience encompasses business disputes, false advertising, consumer protection and fraud, FCA, and extensive class action defense work; antitrust and unfair competition matters; and intellectual property litigation, such as trademarks, patents, and trade secrets.
Jon served as the Nation’s lead environmental civil and criminal enforcement official and litigator, as Acting Assistant Attorney General for the Environment & Natural Resources Division (“ENRD”) of the U.S. Department of Justice (DOJ). Jon led ENRD’s 425 lawyers, overseeing 6,500 active matters and managing an annual budget of more than $150 million. Jon brings highly experienced executive leadership from among the most senior level of DOJ on white collar and regulatory enforcement, as well as on federal policymaking and rulemaking development and challenges. He speaks with authority on government decision-making processes, and the arguments and perspectives that move regulators and enforcers, best advising and positioning clients to deal with challenges.
Jon argued many of the government’s most significant cases during his time with the DOJ. This included the Navigable Waters Protection Rule and Clean Water Rule Repeal (10th Cir., district courts), the Affordable Clean Energy Rule and Clean Power Plan Repeal (D.C. Cir), defense of EPA actions on pesticide tolerances under FIFRA and the FDCA (9th Cir. en banc), among numerous others. Jon represented the United States in trial courts in both enforcement and defensive cases, including federal enforcement action against Jeffrey Lowe and the Tiger King Park, of Netflix fame, securing a first-of-its-kind injunction for violations of the Endangered Species Act and Animal Welfare Act. Jon directed the litigation and briefing of scores of additional federal cases nationwide, covering all of the major environmental and natural resources statutes, such as the Clean Air Act, the Clean Water Act, FIFRA (pesticides), FDCA (food safety), TSCA (toxics), CERCLA (land remediation), RCRA (waste), National Environmental Policy Act, Federal Land Policy and Management Act, and numerous other land- and resource-management statutes.
Jon has unmatched experience litigating legal and technical issues relating to climate change. He argued in the courts of appeals, including the D.C. Circuit, regarding the most significant climate change regulations by EPA, as well as the preemptive scope of the Clean Air Act. Jon also litigated climate change-related credit and trading schemes and international agreements in district court. During Jon’s time in leadership at ENRD, it successfully defeated one of the most wide-ranging lawsuits regarding climate change to date—obtaining a stay pending interlocutory appeal and dismissal just weeks before a scheduled three-month trial on federal government liability for climate change.
An accomplished trial lawyer, prior to working at DOJ, Jon was a partner in the Washington, D.C. office of another global law firm. He not only represents clients in court, but creatively counsels corporations on balancing business needs and realities with a broad range of litigation risks and compliance obligations. Jon is also an Adjunct Professor at Georgetown University Law Center. He served on the American Bar Association’s E-Discovery Working Group for Bankruptcy Practice, and was a frequent lecturer for District of Columbia Bar Association Continuing Legal Education Programs.
Jon served as an appellate clerk for the Honorable D. Brooks Smith, U.S. Court of Appeals for the Third Circuit, after graduating magna cum laude from the Georgetown University Law Center. He worked in state government as an Executive Policy Specialist for air, waste, land remediation, and radiation matters at the Pennsylvania Department of Environmental Protection.
Laurence A. Tisch Professor of Law and Director, Classical Liberal Institute, New York University School of Law; Director, Classical Liberal Institute, Civitas Institute University of Texas at Austin
Richard A. Epstein is the Laurence A. Tisch Professor of Law, at New York University, a senior research fellow at the Civitas Institute at the University of Texas Austin, and a senior Lecturer, the University of Chicago. He received an LL.D., h.c . from the University of Ghent, 2003 , and an LLD h.c . from the University of Siegen in 2018 and the Bradley Prize in 2011. He has been a member of the American Academy of Arts and Sciences since 1985. He has edited both the Journal of Legal Studies (1981-1991) and the Journal of Law and Economics (1991-2001). He is also a founder and director of the Classical Liberal Institute at NYU Law School. His most recent book is The Classical Liberal Constitution: The Uncertain Quest for Limited Government (2014). His other books include Takings: Private Property and the Power of Eminent Domain ( 1985); Bargaining with the State (1993); Simple Rules for a Complex World (1995); Principles for a Free Society: Reconciling Individual Liberty and the Common Good (1998); Skepticism and Freedom: A Modern Theory of Classical Liberalism (2003); Design for Liberty: Private Property, Public Administration and the Rule of Law (2011), and most recently, The Myth of Birthright citizenship—and Beyond (2026). He has taught courses in , administrative law, antitrust, constitutional, contracts, environmental law, land use planning; real property, torts and water law. He has written and spoken extensively on a wide range of topics, and is writes a regular column for Defining Ideas.
Emmett Visiting Assistant Clinical Professor of Law in Environmental Law, Harvard Law School
Andrew Mergen is a Visiting Assistant Clinical Professor of Law and Faculty Director of the Emmett Environmental Law & Policy Clinic. Prior to joining the Harvard Law School faculty, Andrew Mergen served in the Appellate Section of the Environment & Natural Resources Division (ENRD) at the United States Department of Justice. Professor Mergen began his career at the Justice Department in the Honors Program and concluded his career as Chief of ENRD’s Appellate Section. He has presented oral arguments in all 13 federal courts of appeals, including two en banc courts, and before several state intermediate and supreme courts. He has also worked on over a dozen merits cases in the Supreme Court of the United States. In addition, in 2009, Professor Mergen assisted the Office of White House Counsel on the confirmation of the Honorable Sonia Sotomayor as Associate Justice of the Supreme Court. During his career at the Justice Department, Professor Mergen received the Attorney General’s Award for Distinguished Service three times. He also received ENRD’s Muskee-Chafee Award, honoring his work’s significant contribution to protecting the environment.
Before entering clinical teaching, Professor Mergen taught at several law schools including, Harvard Law School (Advanced Environmental Law), the University of Michigan Law School (Natural Resources Law) and the William S. Richardson School of Law, University of Hawaii-Manoa (Administrative Law). Professor Mergen has written about federal water rights in “A Misplaced Sensitivity: The Draft Opinions in Wyoming v. United States” (68 Colo. L. Rev. 683 (1997), with Sylvia F. Liu); energy development on public lands in “Surface Tension: The Problem of Federal Private Split Estates” (33 Land & Water L. Rev. 419 (1998)); climate change and the Endangered Species Act in “The Role of Climate Change in ESA Listing Decisions” (53 Rocky Mt. Min. L. Fdn. 67 (2016), with Murray Feldman) and the accommodation of Native American sacred sites on federal land in “Finding the Path Forward for Indigenous Sacred and Cultural Spaces on Federal Public Land,” 68 Nat. Resources & Energy L. Inst. 32-1 (2022). Professor Mergen is a graduate of the University of Wisconsin—Madison and the George Washington University Law School.
Robert F. Stanton Professor of Law, University of Maryland Carey School of Law
Robert V. Percival is the Robert F. Stanton Professor of Law and the Director of the Environmental Law Program at the University of Maryland School of Law. He received a B.A. summa cum laude from Macalester College, a J.D. from Stanford Law School and an M.A. in economics from Stanford University. At Stanford Percival was named the Nathan Abbott Scholar for graduating first in his law school class. Following graduation, he served as a law clerk for Judge Shirley M. Hufstedler of the U.S. Court of Appeals for the Ninth Circuit and for U.S. Supreme Court Justice Byron R. White. He joined the Maryland faculty in 1987 after serving as a senior attorney for the Environmental Defense Fund. Percival has served as a visiting professor of law at Harvard Law School, Georgetown University Law Center, the China University of Political Science and Law (Beijing), and Comenius University (Bratislava). He is the principal author of a leading environmental law casebook, now in its 9th edition, and the author of several articles about the Supreme Court and presidential authority over executive agencies. Percival wrote one of the first articles on the propriety of consent decrees to effectuate and enforce federal law “The Bounds of Consent: Consent Decrees, Settlements and Federal Environmental Policymaking,” 1987 Univ. Chic. Leg. F. 327 (1987). He also is the author of the first comprehensive analyses of what the papers of the late Justices Thurgood Marshall and Harry Blackmun reveal about the Supreme Court’s handling of environmental cases (“Environmental Law in the Supreme Court: Highlights from the Blackmun Papers,” 35 ELR 10637 (2005), and “Environmental Law in the Supreme Court: Highlights from the Marshall Papers,” 13 ELR 10606 (Oct. 1993)).
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Yale Student Chapter
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Michael Buschbacher, Josh Robbins, Matthew Lee Wiener
The Regulatory Transparency Project and the Federalism & Separation of Powers practice group hosted a...
A Debate on Separation of Powers: Was SEC v. Jarkesy Rightly Decided?
Michael Buschbacher, Josh Robbins, Matthew Lee Wiener
The Regulatory Transparency Project and the Federalism & Separation of Powers practice group hosted a...
A Debate on Separation of Powers: Was SEC v. Jarkesy Rightly Decided?
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Co-Sponsored by the Minnesota Lawyers Chapter, True North Legal, and the University of St. Thomas Law School Student Chapter
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