How has the Department of Defense mission changed with the standup of the Homeland Security Department?

The establishment of the Department of Homeland Security (DHS) in 2003 shifted the focus of the Department of Defense (DoD) towards a more defined role in national security, emphasizing defense against external threats while DHS took responsibility for domestic security and emergency management. This separation allowed the DoD to concentrate on military operations and international engagements, enhancing its capacity to address global conflicts and terrorism abroad. However, the DoD still retains a supporting role in domestic security when requested, particularly in response to natural disasters or terrorist threats. Overall, the mission realignment has fostered a more collaborative approach to national security between the two departments.