Paul N. Stockton was nominated by President Barack Obama to be the Assistant Secretary of Defense for Homeland Defense and Americas’ Security Affairs on April 28, 2009, and confirmed by the Senate on May 18, 2009. In this position, he is responsible for the supervision of homeland defense activities, defense support of civil authorities, and Western Hemisphere security affairs for the Department of Defense.

Assistant Secretary Stockton received a bachelor's degree from Dartmouth College in 1976 and a doctorate in government from Harvard in 1986. From 1986-1989, Assistant Secretary Stockton served as legislative assistant to Senator Daniel Patrick Moynihan, advising the senator on defense, intelligence, counter-narcotics policy, and served as the senator’s personal representative to the Senate Foreign Relations Committee. From 1989 – 1990, Assistant Secretary Stockton was awarded a Postdoctoral Fellowship by the Center for International Security and Cooperation at Stanford, University. During his graduate studies at Harvard, he served as a research associate at the International Institute for Strategic Studies in London.

Assistant Secretary Stockton joined the faculty of the Naval Postgraduate School in August 1990 as assistant professor in the Department of National Security Affairs. From 1995 until 2000, he served as Director of the Center for Civil-Military Relations, assisting over 80 nations to strengthen democratic control over their security forces and deepen security cooperation with the United States. In 2000, he founded and served as the acting dean of the School of International Graduate Studies. He was appointed Associate Provost for Institutional Development in 2001. From 2002 – 2006, Assistant Secretary Stockton served as Director, Center for Homeland Defense and Security, where he helped develop the curricula to strengthen U. S. all-hazards preparedness at local, state, and Federal levels.

Prior to his confirmation, Assistant Secretary Stockton was a senior research scholar at Stanford University's Center for International Security and Cooperation. His research focused on how U.S. security institutions respond to changes in the threat (including the rise of terrorism), and on the interaction of Congress and the Executive branch in restructuring national security budgets, policies, and institutional arrangements.

Assistant Secretary Stockton is co-editor of Homeland Security, a graduate text to be published by Oxford University Press. He served on the editorial review board of Homeland Security Affairs, a quarterly journal he helped establish in 2005. His research has appeared in Political Science Quarterly, International Security, and Strategic Survey. He is co-editor of Reconstituting America's Defense: America's New National Security Strategy (1992). He has also published an Adelphi Paper and has contributed chapters to a number of books, including James Lindsay and Randall Ripley, eds., U.S. Foreign Policy After the Cold War (1997).