Who has the power to declare war?

Congress holds the power to declare war, as outlined in Article I, Section 8 of the U.S. Constitution. This specific delegation of power reflects the framers' intent to balance the abilities of different branches of government. By granting Congress this authority, it ensures that the decision to engage in armed conflict requires deliberation and the consensus of elected representatives, rather than being at the discretion of a single individual, such as the President.

In practice, while the President, as Commander-in-Chief, has significant authority to direct military operations and respond to immediate threats, the formal declaration of war or decisions leading to long-term military engagements typically rest with Congress. This process promotes accountability and oversight regarding military actions, which is essential in a democratic system.

Other entities mentioned do not possess the authority to declare war, as the Supreme Court is primarily focused on interpreting laws and the Constitution, while the Secretary of Defense is responsible for operational military functions but does not have the power to declare war. Thus, Congress is the correct answer because of its constitutionally granted authority to declare war.