A more thorough explanation:

Definition: War power refers to the authority given to the United States Congress to declare war and maintain armed forces.

Examples:

• When the United States entered World War II, Congress declared war on Japan and Germany, exercising its war power.
• During the Vietnam War, Congress passed the Gulf of Tonkin Resolution, which authorized the President to use military force without a formal declaration of war.

The examples illustrate how war power is a constitutional authority that allows Congress to make decisions about going to war and maintaining the military. In the first example, Congress declared war on Japan and Germany, which gave the President the authority to use military force. In the second example, Congress authorized the President to use military force without a formal declaration of war, which shows how war power can be exercised in different ways.