In terms of legislative authority, who has the power to declare war?

The power to declare war is vested in Congress as a whole, which consists of both the Senate and the House of Representatives. This authority is outlined in Article I, Section 8 of the U.S. Constitution, which grants Congress the ability to declare war. This structure was intentionally established by the Founding Fathers to ensure that the decision to engage in war involves representation from both legislative chambers, reflecting a broader consensus rather than being left to a single individual.

While the President does have significant powers as Commander-in-Chief of the armed forces and can engage military forces in certain circumstances under their executive authority, a formal declaration of war must come from Congress. This separation of powers is designed to provide checks and balances in the government, preventing any one branch from unilaterally making such significant decisions without input from the others.