This installment of A&E's popular "Biography" series traces the long career of Donald Rumsfeld, the U.S. secretary of defense under George W. Bush who served in the same post during the Ford administration. A former White House chief of staff, U.S. ambassador, congressman and CEO, Rumsfeld embraced a difficult job before the attacks of Sept. 11, 2001. But it was his performance after the tragedies that would define his public image.