A retired Air Force lieutenant colonel, Dr. Costanzo had assignments in Minuteman 3 ICBM operations and staff, the Office of the Secretary of Defense, and as a faculty member at the Air Force Academy. His expertise and research include the proliferation of weapons of mass destruction, terrorism, and homeland security. His current research focuses on sustaining deterrence and stability at reduced levels of nuclear arsenals. His most recent articles include "What's Wrong with Zero?" and "What's Still Wrong with Zero?", both are critical assessments of the Obama administration's vision to eliminate nuclear weapons from the U.S. arsenal, and "South-Asia â€“ Danger Ahead?", and examination of the potential for instability in the Indo-Pakistani nuclear relationship.