Which power is held primarily by Congress according to the Grand Committee?

The power to declare war and make peace is primarily vested in Congress according to the principles articulated by the Grand Committee during the framing of the Constitution. This allocation of power aligns with the framers' intent to ensure that such significant decisions would be made deliberatively and reflect the will of the people, as Congress is comprised of representatives elected by the populace.

The reasoning behind this allocation is rooted in the desire to prevent any single individual from wielding unchecked military authority, which could lead to tyranny or unbridled aggression. The framers believed that the legislature, representing the diverse interests of the states and the people, should make critical decisions regarding war and peace.

The other powers mentioned, such as selecting the chief executive or voting on constitutional amendments, either involve different branches of government or have specific procedures that do not primarily involve Congress as the sole authority. Coining currency is also a power allocated to Congress, but it is not as directly tied to national security and foreign policy as the power to declare war and make peace. Thus, the correct choice highlights Congress's crucial role in maintaining checks and balances in the nation's governance.