Article I, Section 8, Clause 3:
[The Congress shall have Power . . .] To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes; . . .
The question whether Congress’s power to regulate commerce
among the several States embraced the power to prohibit it furnished the topic of one of the most protracted debates in the entire history of the Constitution's interpretation, a debate the final resolution of which in favor of congressional power is an event of first importance for the future of American federalism. The issue was as early as 1841 brought forward by Henry Clay, in an argument before the Court in which he raised the specter of an act of Congress forbidding the interstate slave trade. 1 The debate was concluded ninety-nine years later by the decision in United States v. Darby, 2 which sustained the Fair Labor Standards Act. 3