Until January 2025, Geltzer served as Deputy Assistant to the President, Deputy White House Counsel, and Legal Advisor to the National Security Council, a role that involved providing domestic and international legal advice to White House leadership on all significant national security matters. Before that, he served as Deputy Assistant to the President and Deputy Homeland Security Advisor, which involved developing and implementing strategies to counter terrorism, protect critical infrastructure, defend election security, and more. For the first six months of the Biden Administration, Geltzer held the position of Special Assistant to the President and Special Advisor to the Homeland Security Advisor on Countering Domestic Violent Extremism, and in that role he oversaw the development of the U.S. Government’s first-ever National Strategy for Countering Domestic Terrorism.
Before returning to government service, Geltzer was the founding Executive Director and Visiting Professor of Law at Georgetown University Law Center’s Institute for Constitutional Advocacy and Protection. Additionally, he was an International Security Program Fellow at New America and an Executive Editor at Just Security.
From 2015 to 2017, Geltzer served as the Senior Director for Counterterrorism at the National Security Council, having served previously as Deputy Legal Advisor to the National Security Council and as Counsel to the Assistant Attorney General for National Security at the U.S. Department of Justice. Prior to those roles, he served as a law clerk to Justice Stephen Breyer of the U.S. Supreme Court.
Geltzer received his J.D. from Yale Law School, where he served as editor-in-chief of the Yale Law Journal; his PhD in War Studies from King’s College London, where he was a Marshall Scholar; and his undergraduate degree from Princeton University, where he studied in the Princeton School of Public and International Affairs.