The reason why I want to be the Secretary of Defense is because I want to serve and help protect America. The Secretary of Defense is second in command(the president is first in command) of the Department of Defense( Pentagon). They provide the military forces with the supply’s they need to deter war and protect our security. The Secretary of Defenses main job is to provide general direction,authority,and control over the military departments. He is supposed to assists the president in all matters relating to the national security.