[stylin19a]

The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.

doesn't say how much to be collected
Probably could keep the 16th and reduce the tax amount on incomes to next to nothing ?

[Sobieski at Kahlenberg Mtn.]

Congress could pass legislation to cap what the rate, but we are talking politicians and as long as the amendment exists it is ripe for abuse by the political class.