The role of the Secretary of Defense in national security is to oversee military operations and policy development. This position involves advising the President on defense matters, ensuring the readiness of the armed forces, and managing resources effectively to address national security challenges. The Secretary also represents the military in international relations, often fostering alliances and partnerships that enhance US security interests. Additionally, they play a critical role in responding to conflicts and crises, making strategic decisions that protect national interests and uphold the country's global commitments.