Benjamin Leff

Benjamin Leff is Professor of Law at American University's Washington College of Law, specializing in U.S. federal tax law and nonprofit organization regulations. He holds a J.D. from Yale Law School and an M.A. in religious studies from the University of Chicago.

Leff's research examines tax policy for charitable organizations, social enterprise governance, and regulatory frameworks for donor-advised funds. Recent scholarship analyzes challenges to the Johnson Amendment, marijuana taxation models, and reforms to public-support tests for nonprofits. His work proposes alternative income security systems and explores the boundary between nonprofit and business sectors.

Leff teaches courses on tax law, nonprofit organizations, and social entrepreneurship. He has practiced tax law in Texas and clerked in Federal District Court. Current projects investigate governance structures for preserving social missions in nonprofit enterprises and regulatory approaches to cryptocurrency philanthropy.