Who has the constitutional power to declare war?

The power to declare war is vested in Congress according to the U.S. Constitution, specifically in Article I, Section 8. This provision grants Congress the authority to formally declare war, a critical function that underscores the legislative branch's role in significant national decisions, such as engaging in armed conflict. The framers of the Constitution established this division of powers to ensure that a check exists on the executive branch, preventing any single entity from having unilateral control over military engagement.

The President, while holding the position of Commander in Chief of the armed forces, has the authority to direct military operations and respond to emergencies without an official declaration of war. However, this power is meant for the immediate use of military force and does not replace Congress's exclusive power to declare war formally. The Supreme Court does not have a direct role in declaring war, as its function is to interpret the law, and the Secretary of Defense serves under the President, assisting in military administration but not holding the constitutional power to declare war.