A more thorough explanation:

War and defense powers refer to the authority granted to Congress under Article I, Section 8 of the United States Constitution. This power allows Congress to:

• Declare war
• Raise and support armies
• Provide and maintain a navy
• Organize, arm, discipline, and call forth a militia

These powers give Congress broad authority to take any measures necessary to provide for national defense in both peacetime and wartime. For example, Congress can implement a military draft or selective service system, as well as wage, price, and rent controls on the civilian economy during wartime.

One example of this power in action is the case of Korematsu v. United States (1944). In this case, the Supreme Court upheld the government's power to exclude Japanese Americans from certain areas during wartime.

Congress also has the authority to set up military courts and tribunals. These courts are not Article III courts, so they do not have the same procedural requirements as civilian courts. For example, a right to a jury trial is not required. Instead, the Uniform Code of Military Justice applies.

Overall, war and defense powers give Congress significant authority to take action to protect the country and its citizens in times of war or national emergency.