Congress has extremely sweeping authority to dictate interstate and international commerce. Article 1 Section 8 of the Constitution:
"The Congress shall have power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defense and general welfare of the United States; but all duties, imposts and excises shall be uniform throughout the United States;
To borrow money on the credit of the United States;
To regulate commerce with foreign nations, and among the several states, and with the Indian tribes;
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"The Congress shall have power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defense and general welfare of the United States; but all duties, imposts and excises shall be uniform throughout the United States; To borrow money on the credit of the United States; To regulate commerce with foreign nations, and among the several states, and with the Indian tribes; "