Conversation so far:
What were John O. Brennan's career highlights?
President Barack Obama nominated John O. Brennan to be director of the Central Intelligence Agency. He was sworn into the office of CIA Director on March 8, 2013.
What is notable about John O. Brennan's time at the CIA?
Two months after assuming his post at the CIA, John O. Brennan replaced Gina Haspel, head of the National Clandestine Service with another unidentified, career intelligence officer and former Marine.
What did John O. Brennan do under President George Bush Jr.?
John O. Brennan defended on TV the transferring of terror suspects to countries where they might be tortured while serving under President George W. Bush.

Question: What was his job in this position?
Self-contained rewrite: What was John O. Brennan's job while serving under President George Bush Jr.?