What constitutional provision allows Congress to exercise implied powers?

The correct answer is the Elastic Clause, which is found in Article I, Section 8 of the U.S. Constitution. This clause grants Congress the authority to make all laws that are necessary and proper for carrying out its enumerated powers. The term "elastic" reflects the flexibility it provides Congress to enact laws that address changing needs and circumstances not explicitly outlined in the Constitution. This provision is crucial for allowing Congress to expand its powers beyond those that are explicitly enumerated, helping to ensure that the federal government can respond effectively to new challenges and situations.

The supremacy clause, while important, establishes that federal law takes precedence over state law, but it does not specifically address Congress’s ability to exercise powers that are not expressly stated. The ex post facto clause prohibits laws that retroactively change the legal consequences of actions that were already committed, and it does not relate to the powers of Congress. The bill of attainder clause prohibits Congress from passing laws that single out individuals for punishment without a trial, which again doesn't pertain to implied powers. Thus, the Elastic Clause is the foundational provision that supports Congress in exercising implied powers.