Which of the following is NOT a power of Congress?

The ability to appoint Supreme Court justices is not a power vested in Congress; rather, this responsibility falls to the President of the United States. The process involves the President nominating candidates for the Supreme Court, which are then confirmed by the Senate. This reflects the system of checks and balances established by the Constitution, where different branches of government have distinct powers and responsibilities to prevent any one branch from gaining too much authority.

In contrast, declaring war, regulating commerce and currency, and borrowing money are all powers specifically granted to Congress under the Constitution. These powers enable Congress to play a crucial role in governance, economic regulation, and national defense. Hence, the distinguishing factor for the correct answer lies in recognizing that the appointment of justices is an executive and legislative collaboration rather than a direct power of Congress.