Jack D. Crouch II
Dr. Jack D. Crouch II (J.D. Crouch) departed service as Assistant to President George W. Bush and Deputy National Security Advisor on the National Security Council in May 2007 "to spend more time with his family." 
Crouch was nominated by Bush on January 31, 2005. 
At the time of his nomination, Crouch was serving as U.S. Ambassador to Romania. "Crouch served as Assistant Secretary of Defense for International Security Policy from August 2001 through October 2003. He was the principal advisor to the Secretary of Defense on the formulation and coordination of policy for NATO, Europe, Russia, the Central Asian Republics, the Caucuses and the Balkans, nuclear forces, missile defense, technology security policy, counterproliferation, and arms control.
"Earlier in his career, Dr. Crouch was the Principal Deputy Assistant Secretary of Defense for International Security Policy. From 1984 to 1986, he worked for the Assistant Director for Strategic Programs in the U.S. Arms Control and Disarmament Agency and was an advisor to the U.S. Delegation on Nuclear and Space Arms Talks with the former Soviet Union.
"Dr. Crouch received his bachelor's degree, master's degree, and his Ph.D. in International Relations from the University of Southern California." 
- Edward Luce, "White House struggles to fill senior posts," Financial Times, May 8, 2007.