Subsection (a) at the link I provided you, listing the "authority" for the Act.
It sure as hell isn't Article I Section 8 of the Constitution.
Re: 15 - okay, thanks.
Agreed about mentioning other countries and world regions.
Re: Art 1 Section 8:
“The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;”
Re: the General Welfare Clause, that ship set sail long ago as to its expansiveness. So things like ESA, etc will be unlikely to be done away with.