Final answer:
The quote refers to Congress's implied powers, which are not explicitly listed in the Constitution but are necessary for executing the foregoing powers. This is subject to debate due to the potential ambiguity in interpreting what is 'necessary and proper.'
Step-by-step explanation:
The quote you provided refers to the implied powers of Congress, which are powers not explicitly stated in the Constitution but deemed necessary to execute the foregoing powers listed. This often becomes a source of debate as there is ambiguity about the extent and limits of such powers, which are inferred from the 'necessary and proper clause'. The clause gives Congress the authority to make laws that are necessary and proper for carrying out its enumerated duties, which includes a range of activities such as regulating interstate commerce, maintaining armed forces, and levying taxes. However, the interpretation of what is 'necessary and proper' can vary, leading to discussions on the balance of power between the federal and state governments.