Section 8 Enumerated Powers

Clause 1 General Welfare

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;

i know congress has passed a few laws pertaining to tariffs but if your are going to change the constitution you need an amendment to do so.