[Poohbah]

What part of that section says that the US government may prevent citizens from engaging in trade?

Sigh. Posted for your edification:

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

Demidog, you're a hoot. You act as if you're dumb as post, but you're a hoot.

[Demidog]

I have read the constitution many times. The excerpt that you post does not give congress the authority to prevent Americans from trading with people of other nations. Regulation is not banning.