Which entity has the power to declare war?

The power to declare war is explicitly granted to Congress by the Constitution of the United States. This provision establishes a system of checks and balances between the branches of government, ensuring that the decision to engage in military conflict is made by the legislative rather than the executive branch. This reflects the Founding Fathers' intention to compel representatives of the people, who are elected to Congress, to take responsibility for such significant decisions.

While the President has the power to act as Commander in Chief of the armed forces and may respond to emergencies or threats with military action without prior congressional approval, formal declarations of war must originate from Congress. This delineation of authority is crucial in maintaining a balance between swift executive action and deliberative legislative oversight, which is essential in making significant decisions that affect national security and the lives of citizens.