Jonathan E. Maddison

Jonathan E. Maddison advises multinational corporations on state and local tax matters, with particular attention to the intersection of federal and state law. His practice covers sales and use tax, income tax, state tax policy, and proposed legislation and regulations. He also advises on constitutional questions affecting tax measures and represents businesses involved in the sharing economy, online marketplace platforms, e-commerce, and the broader digital economy.

Jonathan earned a J.D. from the University of Pennsylvania Law School and a B.A., summa cum laude, from Rutgers University. His academic background supports his work on constitutional law, appellate issues, tax policy, and multistate tax questions. The combination of legal analysis and policy-focused experience helps him evaluate how federal constitutional principles interact with state tax statutes, regulations, and enforcement positions affecting businesses operating across jurisdictions.

Jonathan represents clients in state and local tax controversies and litigation from audit through appeal. His work includes advising on the constitutionality of proposed tax legislation and regulations and addressing disputes involving sales and use tax and income tax. He has filed amicus briefs in the US Supreme Court and the Louisiana Supreme Court for taxpayer trade associations. His clients include prominent companies operating in e-commerce and the digital economy.

Jonathan E. Maddison is admitted to practice in Pennsylvania and the District of Columbia. He frequently writes and speaks about constitutional law, appellate matters, and state and local taxation. His official profile notes presentations for the Tax Executives Institute, Georgetown Advanced Institute of State Taxation, and Institute for Professionals in Taxation. Before joining his current practice, he worked as an associate at Eversheds Sutherland LLP and Reed Smith LLP, adding further experience in complex tax matters and disputes.

Law Office Affiliations

• Founding Member, Roberts Law Group, PLLC
• Member, District of Columbia Bar Association
• Member, Pennsylvania Bar Association

Licensed State

• District of Columbia
• Pennsylvania

Education

• University of Pennsylvania Law School
  Juris Doctor (JD)
• Rutgers University
  BA with Summa Cum Laude

Awards & Badges