Why is the national government responsible for national defense?

The national government is responsible for national defense because it has the authority and resources to protect the country from external threats and ensure the security of its citizens. This responsibility is rooted in the Constitution, which grants the federal government the power to raise and maintain armed forces. Additionally, a unified national defense strategy is essential for coordinating military efforts, intelligence, and diplomatic relations, which are critical for effective defense against potential aggressors. Ultimately, a stable and secure nation strengthens its sovereignty and promotes peace.