Final answer:
The Secretary of Defense (SECDEF) is responsible for military strategy, budgetary oversight, and has a role in foreign policy as part of the president's cabinet.
Step-by-step explanation:
The Secretary of Defense (SECDEF) has various responsibilities in relation to the military, budgetary oversight, and foreign policy. Firstly, in terms of military strategy, the SECDEF oversees the armed forces, including the Army, Navy, Marine Corps, and Air Force.
Secondly, the SECDEF has budgetary oversight, meaning they are responsible for managing and allocating funds for the Department of Defense. Lastly, while the primary responsibility for foreign policy lies with the Secretary of State, the SECDEF also plays a role in foreign policy as part of the president's cabinet.