William Seidleck

As Principal Deputy Solicitor General, William Seidleck’s practice focuses on appeals and high-stakes litigation in state and federal court. William has an extensive background in constitutional law, administrative law, and appellate practice. Prior to joining the Solicitor General’s Office, William served as a counsel in the U.S. Department of Justice, Environmental and Natural Resources Division. William also spent serval years in private practice in Washington, D.C., and as a one-year fellow with the Becket Fund for Religious Liberty. William has argued in the United States Courts of Appeals for the Eighth, Ninth, and D.C. Circuits. He has also helped brief several high-stakes cases in the United States Supreme Court—including a case that overturned a landmark precedent requiring federal courts to defer to administrative-agency interpretations of ambiguous statutes. William earned his J.D., magna cum laude, from the University of Pennsylvania Law School, where he served as an Executive Editor for the University of Pennsylvania Law Review. William clerked for Judge Victor J. Wolski of the United States Court of Federal Claims, Judge Jay S. Bybee of the U.S. Court of Appeals for the Ninth Circuit, and Judge A. Raymond Randolph of the U.S. Court of Appeals for the D.C. Circuit.