Stephen K. Wirth

Stephen Wirth is a versatile litigator and appellate advocate who represents clients in complex, high-stakes litigation across all levels of the federal judiciary. His practice focuses on constitutional and statutory interpretation, administrative law, and cross-border disputes. His clients include multinational corporations, sovereign governments, academic institutions, and major trade associations—both as plaintiffs and defendants—at all stages of litigation. He has briefed and argued cases in the federal district courts, the courts of appeals, and the Supreme Court, and has served as lead counsel in matters involving the Administrative Procedure Act (APA), constitutional separation of powers, the Due Process Clause, personal jurisdiction, sovereign immunity, and the First, Fourth, and Fifth Amendments.

Mr. Wirth has particular expertise in litigation against federal and state governments under the APA and Constitution. He led emergency litigation on behalf of major government contractors and grantees challenging the Trump Administration’s unlawful freeze of congressionally mandated foreign-assistance funding, securing a temporary restraining order and preliminary injunction that resulted in hundreds of millions of dollars in funding being released to his clients. That litigation included a 5–4 victory in the Supreme Court, which left the district court’s TRO in place. Mr. Wirth also has also litigated regulatory actions affecting the pharmaceutical, healthcare, and environmental sectors—including significant victories against the Department of Health and Human Services, the Environmental Protection Agency, the Department of State, Customs and Border Patrol, and the Office of Management and Budget, among others. He has coordinated multi-state litigation campaigns, including a series of lawsuits on behalf of a drug manufacturer challenging state laws affecting the federal 340B drug pricing program.