Constitutional Authority

The United States Constitution states in the 16th amendment:

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.

The 9th:
The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.

Th 10th:
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.

Now the way that I understand supremacy, laws which are enacted by the federal government cannot then be re-created by the states. They can, however, be enforced by the states. Given this understanding, how is it that States can tax income if the Federal Government already does so.

If you review the US Government's argument to the Arizona's SB1070, you'll see that their argument is much in line with supremacy. Specifically:

Both separately and in concert, S.B. 1070’s provisions would subvert and interfere
with federal immigration laws and objectives; the law is therefore preempted.

Now, if this is the main case against the state, would not the Federal Government also be obligated to file similar suit for the subjugation of the people to additional taxation by the states.

I'd suppose you could continue down this line of thinking....